In my country (the US), real estate has been the main source of generational wealth that lifted tens of millions of people into the middle class. In 1950, the median home value was $7,400 [0] ($91,000 in 2022 dollars [1]). The median home sale price now is $440k [2]. Real estate is one of the few tools people have for accessing the power of compound interest, and a very large number of people essentially use real estate as their retirement savings. Supply and demand are major forces that impact prices, and that's why so many people fight tooth and nail to restrict the supply.
I'm firmly in the YIMBY camp (incidentally, I don't own any property), but I grew up near Detroit (1990's-mid-2000's), which is a city where supply vastly outstripped demand, largely because the population of the city declined consistently for decades [3] (which I'd largely attribute to a vastly overbuilt freeway system that enabled quick commutes from the suburbs, and explicitly racist federal housing policy [4]). There were hundreds of thousands of empty homes that no one wanted to buy, and this had some very undesirable effects. For one, many homes in Detroit have such low prices that banks can't justify the fixed costs (inspections, appraisals, etc) involved in backing a mortgage, so instead, people who can't just pay cash have to either rent or enter into a land contract [5], where the buyer pays the property owner every month and gets ownership after paying the entire contract off but accumulates no equity. Another issue of having hundreds of thousands of empty homes (ie more supply than demand) is crime and arson [6]. Empty homes in Detroit often became drug dens/crack houses/shooting galleries (pick your term), and thousands went up in flames every year, either accidentally started by drug users, recreationally started by bored youths, or intentionally started by community members trying to eliminate a blight from their block. A lot of Detroit's issues stem from the bulk of the tax base moving out of the city boundary greatly hindering Detroit's ability to fund police/firefighters/sanitation/other public service workers, so this may not generalize to other situations where oversupply makes real estate not a commodity [7], but I often feel other YIMBYs are a bit myopic about just building more housing without considering the potential impacts (both in the case of overbuilding in cities and the case where adequately meeting demand in cities/suburbs drains demand from exurbs or, or meeting demand in suburbs drains demand from the city). And lest it seem I'm just some white suburbanite dumping on Detroit, I love Detroit and think it's a great city with great cultural and engineering output, and I will always stop in to Lafayette Coney and John R King books any time I'm back.
TL,DR: I absolutely want everyone to have housing and we should build more and employ methods (like high property taxes) to discourage people from simply holding empty property as stores of value, but I've seen what can happen when real estate is not a commodity, and it can be terrible.
[0] https://archive.curbed.com/2018/4/10/17219786/buying-a-house...
[1] https://www.usinflationcalculator.com/
[2] https://fred.stlouisfed.org/series/MSPUS Note: prices not adjusted for inflation; adjust manually before making any comparisons to other times.
[3] https://en.wikipedia.org/wiki/Demographic_history_of_Detroit...
[4] https://www.huduser.gov/portal/sites/default/files/pdf/Feder...
[5] https://detroitmi.gov/departments/housing-and-revitalization...
[6] https://www.detroitnews.com/story/news/special-reports/2015/...
[7] https://patch.com/michigan/detroit/5-houses-you-can-pick-lit...