Housing prices are going up in Sonoma because nobody is building houses (in SF, Sonoma, or any of the other counties in the 9-county Bay Area). Sonoma needs to build as much (well, more thanks to PG&E) as anywhere else out here.
Yes, absolutely. I'd add that this area loves its urban growth boundaries, so the only way to add lots of housing is to build up. This makes the carve-out in SB-50 for counties with a population under 600,000 problematic, in my view.