Dedicating units to low income housing means you've failed to build enough units despite demand, and zoning is likely at fault. Whether it be height caps or parking minimums jacking up the price, they need to go.
We can have $800 apartments inside the city if we so choose, but with zoning forcing developers to build skinny dual towers and similar, we are forcing the minimum apartment price skywards.
Zoning adds risk to projects and creates an overheated housing market, where the cost of housing is land cost, construction costs, & zoning cost plus whatever the seller can get thanks to the artificially constrained supply.
"They aren't making more land" is entirely due to zoning ensuring most of the city is underdeveloped.