The value of a house, like a share, is notional until it is sold. A true decline in house prices will not impoverish the average Briton because the average Briton will not be moving house and those who do will pay less when buying another.
People inheriting may get less than at the top of the boom, but they made no contribution to the original purchase and they will get a substantial windfall given the unprecedented rise in property prices over recent years.