Blame NIMBYs and Euclidean zoning restrictions, which are keeping costs high as a literal goal rather than unintended consequence. It's a supply problem, and government is intentionally discouraging adequate amounts of building, especially building anything affordable, because that's what local democracy dominated by those who want to protect their own property values wants.
Sure, property taxes, building codes, fed-set interest rates, and certain types of speculative investment are all pushing prices up as well, but this is primarily a supply problem and Wall Street's rental giants are literally running out of existing homes to buy.
As a society, we should be encouraging building at a time of high rental costs, not discouraging it in order to protect existing home values for those who already own homes. Much of these are local restrictions, but localities are all filled with Karens who don't want the "wrong kind of people" moving next door.
As a homeowner, I get it. A new apartment building down the street isn't great for my home's value, nor are neighbors subdividing their lots or converting retail to residential if that's what's needed for the community. But we're not anywhere close to running out of land, and were it not for land use restrictions, high rent and housing costs would be sending out huge green flags to construction activity.