Cities can do more than you might think. IIRC some cities plan to cover universal community college, and I know some have universal pre-K. Large cities have health systems.
SF already has free community College. It also has free public Healthcare for the poor (or at least did). Last time I was aware, they changed it so that only illegal immigrants were eligible for coverage.
Like most US community colleges, it was already extremely cheap, ~$2,500/year for a full time student, but this can still be a barrier for some people.