Nobody is going to take their homes away from single-family homeowners on the Peninsula.
The proposal is to upgrade zoning around El Camino, the 101, office parks, and downtowns to allow willing sellers to make even bigger gains by selling to higher density developers. Those developers would be allowed to put up Pacific Heights style tasteful, quality higher density (nothing Manhattan-like).
Or that's the fantasy proposal. I don't think there are any real proposals to make Peninsula development rational or useful to the people who live there. The local politics is content to choke on its overpriced and aging stagnation until some foreign center captures the magic of Silicon Valley.