1. Cities are reaching the limit they can sprawl while still effectively being the same city. Atlanta springs to mind;
2. People vote for politicians who restrict supply to increase the value of something they see as an asset rather than something simply to provide shelter; Increasing house prices are simply stealing from the next generation. That's all. Minimum lot sizes, SFH only zoning, bans on MDU/ADUs, etc all exist solely to increase house prices;
3. Politicians only ever tackle the problem from the demand side eg mortgage interest tax deductions, first home owner grants. All this does is increase the prices by the induced demand. It's a wealth transfer to the existing homeowners.
4. Landlords. In an ideal world, they wouldn't exist. This almost happened in the UK and it was surprisingly simple [1]. They are quite literally and figuratively rent-seekers.
The YIMBYs will tell you "build! build! build!". This is overly simplistic. It also depends on what you build. Look at Manhattan that is building ultra-luxury skyscrapers. There is no trickle down effect here. It's simply money laundering and parking capital.
What we need is a healthy supply of quality, affordable housing. We simply won't get that relying on private landlords. The only solution to thisis so-called "social housing". That is, government owned and supplied housing. Vienna is a prime example here where over 60% of the housing is social housing. Americans will tend to immediately rject this as "projects" or "ghettoes" (or, worse, "socialism").
Housing unaffordability is the number one factor leading to houselessness. It's not even close.
Denying people shelter is, quite literally, state violence. It is causing direct and immediate harm for the sake of wealth accumulation by a few.
So where does rent control fit in all this? It can be a short-term aid at stabilizing prices but it is not a long-term solution. It tends to make it impossible for people to move. Landlords will resort to unethical or even illegal tactics to force out tenants so they can relist at market rates. Or they'll leave units vacant (IIRC there are 100K+ purposefully vacant units in Mnahattan).
Pretty much our entire society is designed to extract wealth from the poorest through rent, student debt, housing debt, medical debt, vehicle debt and maintenance (because in 99% of the US you cannot exist without a car).
Billionaires spend big to block public transit [2]. Why do you think that is?
[1]: https://www.theguardian.com/lifeandstyle/2024/mar/19/end-of-...