The NHS crisis goes on, and its causes are clear: the government’s underfunding of the health service, and the eternally overlooked cuts to funding for adult social care provided by local councils, both of which go back to the 2010-15 coalition. Though some voices issue the usual cliched warnings about the NHS being a political football, the Conservatives – and Liberal Democrats – responsible should not be allowed to slip free of the blame.

In the short term, the solutions are clearly a change of government, and more money. But by 2050 one in four of us will be over 65 – and on current projections, such conditions as diabetes, heart disease, arthritis and Alzheimer’s will be an everyday fact of vast numbers of lives. If we’re not careful, this winter’s horrors could be a portent of problems that will get increasingly worse, whoever is in power.

We seem to have a collective aversion to focusing on the realities of an ageing society. Successive governments (and, let’s be honest, millions of us too) have shied away from the changes – to our food culture, exercise levels, and more – that might ease a mounting sense of dread about the future. Our health service is actually designed to deal only with illness, and the national debate about social care has so far been locked into a moronic argument about whether people will or won’t have to eventually sell their houses.

Besides, for increasing numbers of people, a combination of insecure work and an increasingly punitive and arbitrary benefits system makes the idea of planning for the future look like a sick joke.

But there is an even bigger issue, extending far into the more affluent parts of society, and crystallised in the original definition of ageism coined by the American psychiatrist Robert Butler: “a personal revulsion to and distaste for growing old, disease, disability, and fear of powerlessness, ‘uselessness’ and death”. Far too many of us refuse to consider the prospect of our own advancing years – or, worse still, give any attention to people already dealing with theirs.

Longer lives, clearly, ought to be cause for some celebration

According to the charity Age UK, half a million people over the age of 60 usually spend each day in complete solitude, and nearly half a million more tend not to see or speak to anyone for at least five days in any given week. Half of all people aged 75 or over live alone, 70% of them women. Loneliness and isolation, needless to say, increase people’s risk of developing many of the conditions we now see as synonymous with old age, and which might require residential care.

Longer lives clearly ought to be cause for some celebration. For all the challenges associated with getting older, as the rabbi and writer Julia Neuberger put it in her 2008 book Not Dead Yet, the years over 65 should ideally be a time of “coming alive”: a stage when we can “take a bit of a risk” or rejoice in being “plain stroppy”; a phase of life, moreover, in which many people can take on ageism by becoming “grey panthers”. By the time people of my generation reach later life – and I am 48, so it is not that long off – we will surely have the tools to be a spectacularly assertive lot, wired into online networks.

Illustration by Patryk Sroczynski.

Yet serious obstacles to this vision remain. One is to do with work, and the need for both an end to “cliff-edge” retirement, and for a culture that might allow something more than the stereotype of an older person either collecting supermarket trolleys or putting in unpaid hours at a charity shop. Another is about how and where we live, and a national trait that does older people no end of harm: the fact that Britain remains a place where home is a byword for retreat and seclusion.

We also seem to cling stubbornly to an ingrained conviction that even manageable need and frailty are always best dealt with by professionals dispatched by the state. Both ideas are embodied in those forlorn clumps of older people’s housing you see regularly in small towns: compact, self-contained bungalows and flats, whose designers seem not to have thought seriously about how to promote shared social bonds, or allow people to stay as active as possible.

There is an alternative. Cohousing was invented in Scandinavia, and is now slowly being popularised elsewhere in Europe, and in the US. The idea is simple enough: to quote from the explanatory blurb used by the UK Cohousing Trust, it boils down to “intentional communities” – they tend to number about 25 households – in which each household “has a self-contained, private home as well as shared community space”.

If you accept that a big part of how we manage an ageing society will come down to what some people call support networks, here is a possible answer – one that is currently too often frustrated by the economics of housebuilding, hidebound local politicians and housing associations, and what one report calls “a tradition of institutional paternalism in relation to older people and ageism”.

There are reckoned to be 19 cohousing projects in the UK that are up and running, with another 60-odd in development. Most of them are multigenerational. But there are a number on the way that are devoted specifically to older people, following the example set by New Ground, in High Barnet, a women-only community founded by the Older Women’s Cohousing Group, and built after 20 years of work and struggle (the youngest resident there is 51, the oldest 88).

Later this year, people will start to move into Cannock Mill near Colchester – where 23 older households, split between single people and couples, will live in houses and flats spread around a shared “common house” and allotments. It is almost full, and its waiting list apparently includes forward-thinking people who are currently in their 40s.

“Our aim is to delay the point at which you need to go into care by the way we live,” one of the prime movers told me this week. “A lot of illness in old age is related to social isolation. That won’t happen to us, because we’ll have a permanent community.” Homes will be easily adaptable, so as to include extra fixtures – internal lifts, for example – where necessary. The shared space will include a kitchen area and dining space big enough for all the residents to eat together.

I know: thanks to a mixture of unease at the prospect of getting old and the belief that hell is other people, a lot of younger onlookers might recoil. But that is the crux of a very British problem, and it has one pitiful upshot: the fact that our visions of later life are in danger of collapsing into despair, when we ought to be building them on imagination and hope.

• John Harris is a Guardian columnist