They might be the biggest group of home owners, but they’re not themselves the issue. The optimal situation would more or less be every family owning a single home.

If house prices go down equally across the market, single home owners don’t really lose out because people typically sell houses when they want to buy a different house. People who recently took out big mortgages will complain about negative equity and some idiots are happy to see a number go up but by and large single home owners will be fine and won’t even complain a lot - they know from their children or other sources that its too damn expensive to buy a house.

The real losers would be people who own property as an investment, and developers. And those two groups have powerful lobbies and the majority of politicians are in the first group.

The single home owner NIMBYs are a problem in cases where prices will be affected but only locally. Then they really stand to lose out. So you basically need to have a massive nationwide house building program, either done by the state or through strong legal incentives to force developers to build a lot more of the right kind of homes and prevent them from sitting on land waiting for the price to go up. Or probably both.