Fashion moments come in all shapes and sizes and are not necessarily of the high-octane, flashing shoulder-pad variety. A case in point. After the unveiling of Stella McCartney's autumn/winter collection in Paris early in March a heated debate ensued. In the red corner, the mere idea of a designer sending out nothing more show-stopping than a pair of narrow-legged wool trousers, a loose-fitting cashmere sweater and a pair of kitten-heeled, sling-backed court shoes (yes, kitten-heeled, sling-backed court shoes) was seen as unimaginative. Yet McCartney did just that. We don't need a catwalk for clothing as straightforward as this, surely, the thinking went, and given a world now used to and even blasé regarding grand gestures it's easy to see why. In the blue corner, though, a rather more interesting argument emerged. We all know that this is not the world's most innovative designer – neither, in fairness, does she claim to be. Instead, McCartney, at her best, is a woman designing functional clothing with her friends, in this case other women, in mind. The point was that the look in question is one that might formerly have been reserved for the business-like showroom appointments that follow the high drama of a catwalk presentation, where buyers place their orders and the more obviously commercial side of a collection is displayed. This time, the more obviously commercial side of the collection was the statement and one that was therefore radical for its very conservatism.

Neither was McCartney alone. Nothing more outré than camel coats and roomy trousers were the scene-stealing look of the season for the Chloé designer, Hannah MacGibbon. More trousers, not of the dropped crotch, awkwardly cropped variety that have been fashionable for some time, but ultra-flattering, high-waisted and ( whisper it) very slightly bootcut came courtesy of Frida Giannini at Gucci. Navy coat dresses (not quite like those the Queen likes to wear but still) and black boots with an only averagely high, burnished gold heel were the order of the day at Phoebe Philo's apparently indomitable Celine. It seems not insignificant that these are all female designers, indebted, for the time being at least, not to any street-inspired, too-cool-for-school aesthetic but to the creation of timelessly elegant pieces that will serve their wearer well for seasons and even years to come, and work everywhere from the boardroom to the (generally not even remotely cool) school gates. Neither is it surprising that as these women have become older, they have cast aside any obviously seasonal – or sensational – preoccupations in favour of a more enduring mindset as perhaps best befits their own lifestyles.

If the women stood out, they were by no means the only ones to tap into this mood. The Burberry designer, Christopher Bailey, followed the barely-there chiffon dresses and equally teeny-tiny trench coats that filled his summer collection with flight jackets, parkas and even a classic pea coat for autumn. Hussein Chalayan sent out an idiosyncratic spin on the type of slick, early-Nineties tailoring that once made the heart of any Uptown Girl worth her credentials beat faster. Across the board there were fisherman knit sweaters, neutrally coloured classic outerwear, skirts in all shapes and sizes just so long as they were below the knee, bearing modesty in mind, dominated. Modesty? That's a word that hasn't been used concerning contemporary fashion for a very long time. Footwear, meanwhile, given a collective consciousness familiar with designs so far-fetched they resemble gravity-defying machinery or the claws of sequinned lobsters rather than mere sandals, was, equally, nothing short of sensible by comparison. As for the now defunct "It" bag, anything stamped with logos or weighed down by hardware is henceforth banished to fashion Siberia. Instead, satchels worn across the body leaving madam's hands free to follow pedestrian pursuits such as actually being able to reach for her purse, neat little clutches and paper-flat totes with barely a fastening or designer name in sight are the things to see and be seen carrying.

To drive fashion's new message home, the cover of Vogue's August issue – the one that introduces the new collections to any interested party in this country at least – reads "THE RETURN OF REAL CLOTHES". And, in a world now saturated with garments so short and/or tight and/or revealing and/or whimsical, they invariably dare a woman to wear them over and above gently enticing her into their luxurious folds, it is the very pragmatism of this quietly revolutionary new aesthetic that makes it remarkable.

It's not news, of course, that the type of here-today-gone-tomorrow trend-driven designs that characterised the first decade of the new millennium are now about as fashionable as a loaf of sliced white. Neither is it any longer appropriate to view fashion as disposable. The rise and rise of budget copies of designer clothing that meant a new outfit for every day of the week for any fashion knowledgeable woman aged between 14 and 40 appears at best outmoded, at worst plain irresponsible. Conspicuous consumption, be that ironically dipped into by the chattering classes, or heartfelt in unashamed WAG/Sex in the City manner, has lost its legs. Instead, never has the term "investment piece" held so much sway. And investment pieces are best either precious to the point where they may be handed down as heirlooms and tend to be available to only the very few – hence the relative buoyancy of haute couture – or under-stated, with none of the tell-tale detail, indulgent frills, furbelows and bare-faced folly that will render a garment irredeemably dated six months down the line.

"I'm into clothes that are practical," Philo tells Vogue. "I don't like being held back by what I'm wearing. I like comfort and ease. I don't need more complications. There are enough challenges." And here's Gucci's Frida Giannini talking in equally down-to-earth terms. "There's less of a desire for show-off fashion," she says. "What I want is beautifully chic clothes that make me feel like a woman." Their words could be the mantra for the season as a whole.

Of course, now, as always, fashion is a cultural barometer reacting to the social issues of the age. And so, just as the pared down looks of the early Nineties were a backlash against the type of over-blown, highly staged aesthetic represented by Thierry Mugler, Claude Montana and more, today's understated mindset marks a similar move away from both fast fashion and the exorbitantly over-priced statement dressing best exemplified by Christophe Decamin's 1980s-obsessed Balmain, where a pair of jeans might cost upwards of £1,000 and a sequinned T-shirt rings in at almost three times that amount – and that's with or without intentional ageing. With this in mind, and safe in the knowledge that there truly is nothing much new in fashion, the work of the original minimalists – Prada, Jil Sander, Yohji Yamamoto and, perhaps most noticeably, Helmut Lang – who rose to fame during the recession that hit back then are currently being referenced by a new generation eager to tap into an equally modern – and understated – mindset now that the entire luxury goods industry teeters on the edge of economic meltdown once more.

Here's American Vogue's Anna Wintour commenting on Lang's impact in particular more than 10 years ago. "Helmut came along and at first it was 'Wait a moment, what's this? This is not the spirit of the mid-Eighties which was all about opulence.' But then everything crashed and fashion reflected that and Helmut was there to take advantage."

While it would be unfair to argue that any new-found reality check is taking advantage of financial uncertainty, it is doubtless the case that serious times demand serious clothes to match. To flaunt one's wealth is no longer appropriate – cash just isn't classy right now. Not everything in this most practical of all possible worlds is quite as simple as all that, though. It should come as no great surprise that both Prada and Louis Vuitton – Miuccia Prada and Louis Vuitton designer Marc Jacobs are both notable for the fact that they set the mood as opposed to fall in with it – are following a discreetly different path. While both these superpowers might appear – and even claim – to be designing real clothes for real women, it is here that it becomes crystal clear that such labels remain relative.

"It's normal clothes. Classics. Revising the things I did in the Nineties," Miuccia Prada told Style.com backstage following the unveiling of her autumn/winter collection in Milan. To this designer's mind, however, "normal" denotes a heavy black wool 1950s-line dress (sleeveless) with conical breasts built in, Aran knitwear so chunky it is far from obviously flattering, ribbed tights in the colours of sludge that, again, all but the stick thin of limb will find far from easy to wear. Miuccia Prada's reality, you see, dictates that "normal" doesn't necessarily mean easy or rooted in vanity and hats off to her for thereby lifting even a comparatively restrained collection way out of the realm of the banal. Over at Louis Vuitton , meanwhile, where the show notes announced "And God Created Woman" and Elle Macpherson returned to walk the runway for the first time in years, the aim was clearly to promote a more grown-up and curvaceous aesthetic. Macpherson might be more grown-up and curvaceous than most of today's models, but let's not forget that she has long been known as "the body". She's hardly Everywoman, appearing not only exceptionally long and lithe but also a good 10 years younger than her years.