A friend mails from Edinburgh: “The referendum is all anybody talks about. My mate is getting married next week and says despite that, all his dreams are about independence.” An uncle born in Rangoon, but living in London for 50 years, comes to visit with one thing on his mind: “I can’t hear enough about what’s happening in Scotland.”

Britain is in the middle of something so epic that almost everyone feels compelled to have a view on it. And like a Rorschach test, both right and left gaze upon the saltires and the protesting crowds outside BBC Scotland – and see exactly what they want to see.

For the right, this is an insurgency of the subsidy junkies: a coalition of the ungrateful, the unaffordable and the utopian, hell-bent on disrupting an order that has provided three centuries of stability. Seen from the left, this is an uprising by capitalism’s oppressed, throwing off the shackles placed on them by Thatcher’s children and the Blairite zombies they are just a vote away from a socially just Xanadu. I exaggerate a little, but – after all the afternoon rallies and midnight blogs and front-page warnings from the Queen – I’m not alone.

The fundamental point, though, is this: neither picture captures the reality. Look at Scotland’s economic profile, and it’s clear that independence would be viable. But count up the building blocks that would form the basis of a new economy, and it looks sadly unlikely that an independent Scotland would be much of an alternative to the Old Corruption south of the border.

None of the above is going to stop the no campaign from keeping the union together at all costs. Which is why this weekend’s newspapers were bursting with dreadful warnings from Deutsche Bank about how a yes vote would be “a political and economic mistake as large as Winston Churchill’s decision in 1925 to return the pound to the gold standard” or the missteps in Washington that triggered the Great Depression.

That note of alarm came from the foreword to a two-page research note issued by Deutsche. Over the year, I have read thousands of such finance-house briefings – indeed, I have dim memories from very early in my career of having contributed to a few – and can say two things about them with confidence. First, for all the numbers and letterheads, they are not the word of God. They are a cross between a commentary and a forecast: think of a horse-racing tip without the colourful names, or Simon Heffer with more graphs. The Deutsche paper fits the form to a T: the bank’s group chief economist’s remarks are less economic than political in nature. “Why anyone would want to exit a successful economic and political union … to go it alone for the benefit of ... what exactly, is incomprehensible to this author.”

Fair enough: it’s one man’s view. But the other rule of research notes is that there’s bound to be another expressing a contrasting opinion. Such as the email I received from the head of the global strategy team at Société Générale. It argues that a yes vote would lay bare the fact that, without Scotland’s oil exports, the rest of the UK simply doesn’t pay its way in the world – and so independence would see “sterling quite rightly plunge into the abyss”.

Two well-known financial strategists, two divergent views – but only one gets amplified by the media. Funny that.

To make the sort of call issued by the Deutsche economists, you would need the kind of information about who would get what share of the oil and of the UK’s debts that we just don’t have yet – because those negotiations between Holyrood and Westminster haven’t even begun. Despite that, the no camp leaps on any passing argument to support its side. Even if they are pish. You can’t argue both that a go-alone Scotland would be as overbanked as Iceland, and that RBS and Lloyds leaving spells disaster: it’s one or the other.

That said, the technicalities mean the transition to independence would be turbulent. Forget about devo max; there would be austerity max, thanks to Scotland’s budget deficit. Worried over the value of their assets, savers and companies would try to shift their money south. Thousands of business contracts would need to be redrawn.

If the Scots go into currency union with the rest of the UK, their interest rates, financial regulation and probably their tax-and-spend policies will be dictated by the entity they have just opted out of. The plan B of merely adopting the pound would be even worse, and leave banks headquartered in Scotland in need of a new lender of last resort. As Dundee-born economist Mark Blyth points out, the most sensible option, of a Scottish currency, would take about five to seven years to set up a new central bank, a new bond shop and a new tax office.

These are just the technicalities – and they already spell a decade of pain. But provided the new country’s electorate was primed for such sacrifices, they could be got through. The big question for the left, both in Scotland and the rest of the UK, is what kind of alternative economy would be built. And I can’t see that it would be so different. Adopting the pound or the euro would bind the new country into the same old hated structures. Going by SNP policies, this new small state would follow the path trod by many of its predecessors over the past two decades: cut corporation tax, sell assets and try to draw in as much foreign capital as possible. The result wouldn’t be Sweden, but Ireland: a plaything for big multinationals.

It wouldn’t be impossible to craft an alternative economic policy: but there isn’t one in place yet. Ask for one and you are pointed to the Wee Blue Book or Adam Ramsay’s 42 Reasons: both are smart, generous-minded critiques of Britain’s political economy, but they are short of concrete alternatives. Ask for an alternative to Alex Salmond and you’re shown “good bloke” Patrick Harvie. But the Green party he heads polls about as well north of the border as Ukip.

In the old days of ethnic nationalism, having a vacuum in place of an alternative wouldn’t matter so much: separatism would be an end in itself. But the yes campaign that’s emerged over the past few years is built around a civic nationalism, in which the forming of a nation is only the means to an end of progressive values. Trouble is, around the central issue of economics, there is a blank ready to be filled by the old conservatism and lobbying.

• This subheading was amended on 15 September 2014. An editing error resulted in Iceland originally appearing where Ireland was meant. This has now been corrected.