Santa Cruz may be very "near" the Bay Area geographically but it's not practically. Even if you worked in San Jose you're talking 1.5 hours of commute in good weather (I did that for years). The other closest city is Monterey which is further and is of course not what anyone might call an economic hub.
Most of the people living in Santa Cruz owning homes are not commuting to the Bay to work. They made their money in tech and have retired to the beach.