Mrs May, the soon to be crowned Tory prime minister who promises to end Conservatism’s embrace of neoliberalism, is also the woman who will end the 40-year property boom. British house prices are absurdly high in relation to incomes – in national historical terms and in comparison with other countries. Their fall has long been inevitable, but less obvious was what would cause it.

Now we know. A decade of wage stagnation and the coming recession – perhaps depression – occasioned by unnecessarily rupturing our economic ties to Europe will together cap their growth. But it will be the many, many home sales (some estimates suggest around 100,000) to pay back the care bills to the government under Mrs May’s proposed backdoor inheritance or “dementia tax” that will deliver the coup de grace. June 2017 will be when house prices reached real-time highs not to be equalled for decades.

It is a by-product of Mrs May’s promise to tackle intergenerational inequity. Britain’s over-65s, four-fifths of whom are the owners of housing wealth on a scale unequalled in any advanced country and whose pensions have been growing, have been phenomenally privileged. For as they prosper Britain’s young have faced double-digit declines in their real wages, along with house prices so high that the average first-time buyer is now in her or his mid-30s.

Mrs May is as good as her word in addressing this unfairness, turning her back on the policies of her predecessors and coming up with an eye-catching triple whammy. She has abandoned the winter fuel payments for all but the 2 million poorest pensioners; scrapped the guarantee that state pensions will rise at least 2.5% a year. And, crucially, she has replaced David Cameron’s proposed £72,000 cap on care bills with her plan that those whose savings and property are valued above £100,000 will need to pay for their care.

This is a direct assault on the Conservatives’ electoral base of the over-65s, a third more likely to vote than the rest of the population and half of whom vote Tory. That takes some chutzpah.

It is also vital. Very few comprehend the scale of the Britain’s impending economic and budgetary challenges. Over the next 20 years, Britain’s pensioner numbers will rise by 40% to more than 16 million. As a result, in 2035, spending on pensions, social care and the NHS – if policies had remained the same – would have been £40bn higher in real terms than it is today (a rise of 2.5% of GDP). Spending on the old, sitting on fabulous (relatively speaking) housing wealth, would have crowded out everything else, made worse by the disintegrating tax base triggered by the economic consequences of Brexit. It was an impossible prospect.

Of course, this stride towards intergenerational fairness is disfigured by a substantial stride backwards – the retreat from a social insurance approach to social care. The manner of death is not in anyone’s hands. You may be lucky like the majority and die peacefully, requiring not much money on care bills except for the last few months. Or you may be unlucky and suffer from infirmity or Alzheimer’s or dementia. In which case you will be among the 10% whose care bills could climb above £100,000.

This is what moral philosophers call brute bad luck. You and your family did nothing to deserve this – no virtuous lifestyle nor prudent saving could have prevented it. The correct response is collectively to insure ourselves, like we do for the risk of a fire or a car accident, so that if we do have the bad luck to have an expensive old age the insurance will take care of it. To keep the cost of the insurance down, there can be a cap on payouts after which one has to pay for oneself.

This was the Cameron approach with the cap of £72,000 and the paradox is that the opponent of “selfish individualism” and champion of mutual obligation should insist on the reverse for the elderly. Mrs May does not recognise the role of brute bad luck in the policy towards social care; rather, there are warm words about the importance of saving for old age rather than relying on the taxpayer – and then the same philosophy is used to justify asking the taxpayer to be paid back for care bills from property sales after death. In this universe, all luck is deserved and social insurance is only another way of raising taxes.

There is a more perfect world, that inhabited by moral philosophers and rational economists such as Andrew Dilnot, author of the Cameron scheme. In this land, Britain would adopt social insurance for the old and live Mrs May’s self-declared principles. But in the world as it is, there is the reality of approaching £5tn of housing wealth sheltered in the world’s largest onshore tax haven. In the more perfect land, both main parties would be recommending a revaluation of property values, introducing a proper council tax, reducing the exemptions on inheritance tax and perhaps even a small tax on capital gains on housing. All are off the agenda, despite the fact that the owners of this wealth simply had the good luck to buy a house before today’s under-35s. They did nothing to deserve this wealth, but they are insulated from tax.

In this context, the “dementia tax” as it has been dubbed – dementia sufferers living at home will now have their social care bills deducted from their estate after their death – is a smart way of taxing the housing wealth that would otherwise be untaxable. In moral terms, the spoils of undeserved brute good luck will pay for the costs of undeserved brute bad luck – and the state gets resources it otherwise would not. On top, house prices will be lower than they otherwise would be.

There will be millions who skip free and pay neither social insurance nor the new tax and can enjoy the good luck of their housing wealth unalloyed. Britain would be a fairer society if it could reshape its property market and property taxation – and if it could organise welfare around the social insurance principle. But the future is the one defined by Mrs May who has, for the moment, freedom to do more or less what she chooses. It may be imperfect, but there will be more intergenerational fairness than there was before. For that at least be grateful.