The target candidate for these startups largely doesn't exist. Most folks accepting such a salary in the Bay Area are recently out of college and living in small apartments with roommates.

When it's all said and done, most of these startups will settle for a few offshore contractors or hire remote people who live in cheaper parts of the country where $90K goes a lot further.

The tried and true "solution" to this problem is to import a number of H1b visa holders from other countries who are willing to work for the lower salaries and accept the lifestyle choices that it imposes in the Bay Area. For many of them, $90K in the Valley is still an upgrade from where they are coming from.

For those of us with a decade or more of experience, it's best to focus on the post Series A startups that have the money to pay. However, many of these jobs involve cleaning up code written by those inexperienced folks who accepted less pay in the early days.