Perhaps they shouldn't have taken out such a large mortgage then? lol. People don't bat an eyelid when a car loses half it's value the second you drive it off the forecourt, why are we so obsessed with houses doing the opposite all the time? I'm not denying in the short term it'd be a kicker for some people in certain situations, but if it's for the greater good then so be it. I don't think it'd be more expensive for most people, for what it's worth.
I broadly agree with the point that houses should be within reach for normal people in normal jobs, it's a societal good, you need people to be able to create their own security to be invested in society etc.
Your attitude and tone comes across as super salty though and those same people who would benefit from the changes you're suggesting are also currently dealing with the world as it IS because you can't pause life and therefore would be badly hurt if it happened too quickly. It's easy to say "tough" when either you haven't gotten involved yourself or are shielded from it, whichever it is I guess that's why you sound a bit trolly about a genuine problem.
We need to make changes like changes to taxation/multiple ownership/building etc but going to fast would create a very toxic situation that would help no one. I'm not sure if you remember but the last time we had a wobble about what houses were "worth" we had a massive recession, a decade plus of austerity (ideologically driven for sure but it still happened and the Sun etc whipped the public into mostly supporting it) and a ton of people lost their jobs/job security.
It's not just house prices that need to be considered because sadly that is now most entirely normal people's main asset that they've signed up on mortgages over long periods to pay for and sneering at them is not helpful. Nobody is signing up on 120% mortgages or self certs anymore because they don't exist and you don't have the option to not live somewhere.
Which is why your car analogy is pure derp. A car is a consumable, you use it until it's used up and then it's worthless and you switch it (broadly speaking). A house is not that, in fact a good chunk of the "value" of your house is the land it sits on not the doors and windows.
Which is why I honestly believe it needs to be a generational thing.. A slow decline/stagnation I believe is what's required.
That way you create stability for people to get on the ladder, burn or disinterest the speculators etc.
I personally believe the only way to get there is a massive government house building project, rent controls, long term leases and developer subsidies.
We're not going back to 3x salary buying you a house anytime soon, we just need to forget about that. It's not as if that was forever anyway, I suspect it's been not like that for longer than it ever was like that. We didn't have mass ownership must before the 50s/60s anyway.