But what do they actually do, and why do you need a startup to do it? Hanover, NH has a housing price problem, but Dartmouth College offers subsidized housing to its faculty. Why can't school districts do the same?
It should be understood that current circumstances have no precedent in history and show signs of market dysfunction. Just as most famines are complicated if not caused by market failures so the current lack of housing appears to be related to systemic failures. It is no coincidence that we are seeing rapid increases not only in people without homes but also homes without people at the same time as high end luxury estates intended as financial gambling chips go for decades without any residents moving in.
No idea why the direct link to that is broken.
Anyway, it looks like, they pay your down payment, then take 25% of any profit when you sell.