I'm not sure I can grasp why you're so negative about house ownership and you seem to be rather in some weird ideological cage that doesn't let you see the whole picture. Firstly you have something akin to the broken window fallacy going on: if I buy a house someone else (often a company) gets that cash and can invest it. The money does not disappear, and if I had taken the same loan (which I likely wouldn't have received without the house title as guarantee that the bank gets its money back) to start a company or invest in stocks there's a much higher probability of failure than that my house disappears. So it's a thrifty investment.

In particular as secondly, house ownership means I'll save on rent, rather than to pump money into someone else's pocket I'm accumulating the value. It's a simple calculation that this is in most cases in my benefit if I expect to be in the same spot for 5+ years. Real house value could even decrease over time, the rental costs I'm saving could still make it a good investment.

Thirdly, first house owners are unlikely to try to influence policy just to increase house value. Not sure how you can have such an idea, for most owners this would be unlikely to be worth the time& effort required just to increase house value 1℅ or so. But you can be sure they will fight for their quality of life (think parks, no planes, etc). That coincides with house value but for most average citizens the only (conscious/driving) reason to affect local policy is quality of life.

And lastly I think you're somehow too far from reality if you argue it is in an individual's interest to serve the wider economy. I'm not going to use my money just to benefit an imaginary wider economy - what is the benefit then for me? Why be rich if life sucks (and why risk all my money just to start a company if I have already a good income & life?) Do I live just to nudge Gdp up by 0.00001℅ over my lifetime? Or do I want a healthy life, a garden for my kids to play, etc.

Buying a house is a very rational decision and I"m not sure what you can see as selfish (in particular considering point 1). Your argument really is somewhat absurd and I find it hard to believe you make all your life decisions or buying decisions with such an approach (leasing your laptop? Living in a polygamous commune as keeping an attractive partner to yourself would keep potential value from the rest of humanity?).