In other words, rental yields are low in those places. Probably because the prices are expected to increase, so the owners benefit from capital gains rather than rent. Definitely should be a temporary phenomenon though. Prices are falling in a lot of high-priced urban locations, eg. London.
https://smartasset.com/data-studies/price-to-rent-ratio-in-t...
In other words, rent is high in San Jose but renting is cheaper than buying in places like that.