You are arguing as if buildling more make things worse, when in fact, this is not the case. The opposite of buildling more is building less. Building less will increase existing price a lot more on an existing neighborhood than building a new buildling will ever do.

When there's not enough housing for people to live in, people start competing on rent and bidding wars on purchases, this drives price very fast.

That's why you have to build more. To avoid the biggest issue which is a housing shortage.

Is that the ONLY solution? Of course not! Public housing is great. But the same things that prevent YIMBY policies is the same thing that prevents public housing to be built. When you advocate for more zoning to prevent new condos in your neighborhood, it's not just new condos at market price that will be prevented, it's a whole range of housing.

>When there's not enough housing for people to live in,

In the country I live in, our population is a shrinking. Quite literally. There would be fewer people today than last year, and will be fewer people next year than this year. Except...

> Public housing

You can't have Vienna style public housing without having Vienna style zoning codes and building codes.

Most of the housing in Vienna would be illegal to build in like 99% of American cities.

"Upzoning increases land value. Developers build profitable market rate houses there"

Unless you are upzoning ONLY in low-income neighborhoods, this doesn't add up. The assumption is that upzoning makes development more attractive. But this would apply to the entire city, and would therefore increase housing supply outside those low-income neighborhoods as well, which actually reduces the propensity for displacement.

Public housing construction typically has to follow the law as well, so how does it help in cities where increasing housing units is heavily restricted, and outright banned in 90%+ of the city? YIMBY upzoning is strictly necessary no matter what funder you want for development.