Not necessarily. Bubbles are based on speculation. The last bubble was powered by sub-prime mortgages, which is what burst.
The Bay Area has the problem of ongoing immigration, a very highly paid demographic, and housing market that isn't keeping up. Simply, Offer < Demand.
Offer isn't looking to catch up any time soon [1], and demand crashing would mean the tech economy will have crashed as well (or, you know, The Big One).
[1] I'll have to sleuth up the link from 6mo-1y ago about how maximizing consctruction at this point would only keep up with demand, effectively only preventing a further increase.