It's really hard for employees 1-N, especially at sub-market salaries, but without 10% equity stakes, to move to SFBA. It pretty much restricts you to people already-here, people who will live college dorm style, or people who are already well off. Too much of the money raised goes out the door in salary (taxed) to pay for housing.
I was really excited by Campus, and hope we see a lot more startups with similar ideas.
Above, you mentioned a "bandaid" solution of increasing funding for YC founders to account for skyrocketing rent - but this only exacerbates the problem for everyone else, including YC companies' employees and the entire ecosystem that supports them.
Tech workers' willingness and ability to pay ever-increasing rent, underwritten by salaries drawn from irrationally exuberant venture capital investment in tech (low interest rates elsewhere), is driving a housing bubble that, in a vicious cycle, is then further fueled by property investment justified by ever-increasing rents.
I guess I was looking more for YC to take a leading role here in proposing solutions, rather than passively hoping for a fix. The simplest, as it seems to me: open a bleeder valve by providing incentives for successful YC companies to "settle" other startup hubs, or even just acting as a broker for bidding by those locations. I'm sure there are smarter fixes, but I can't see the harm in enacting these.
YC has done a little bit of this informally (Alexis as "Ambassador to the East"), and a lot of YC founders are from other places and retain hiring/offices/etc. in those other places. There are lists, support networks, etc. I know of for YC companies resettled in Seattle, and probably in other places.
There are also some YC companies which are explicitly "X for India", "Y for Brazil" where they obviously are based in those other places.
There ARE a lot of YC companies which want to remain in SFBA, though, so looking at options like Campus (RIP; wonder what happened; would love to talk to the founder for a post-mortem) makes sense, too.
Startups aren't going to move, like you suggest, although the bigger companies are willing to open offices elsewhere.