It also is harsh on those who borrowed money to buy a house, with the idea to pay back part of it over the years, and, after retirement, move to a smaller house

It also is harsh on those who borrowed money to buy a house, with the idea to pay back part of it over the years, and, after retirement, move to a smaller house or a house in a less desirable place, and use the price difference to pay back their mortgage and, with the rest, fund their pension. And no, that doesn’t mean those people speculated. Even if prices stay flat, that could mean they got a decent lump sum from such a move.