All of these things cry out for regulation, but vested interests are strong...
1. PE ownership of rental properties. They move in when they identify an arbitrage advantage between rental income and purchase price. When the market inverts, the property values of first-time property owners in those neighborhoods start to tank.
2. Outright price collusion by large-scale landlords using AI. IMO, this is more significant than currently believed.
3. single-housing zoning regulations, often a historic vestige of trying to keep black people out of neighborhoods. People have a strong aversion to living in neighborhoods that include multi-family housing, and it is a limiting factor on ownership rates for the young. Even progressive areas have had difficulty in addressing legacy zoning issues.
4. Air B&B - this reduces affordable housing stock in cities and tourism areas. If you're renting your property on a short-term basis more than three weeks a year, you are a hotel and should be regulated and zoned accordingly.
Point 2 is illegal and points 3 and 4 are outright regulatory arbitrage, but the cries of "free market" from opponents is maddening.