Generally, a start up founder should be more interested in growing the company's (his) equity as opposed to taking a paycheck. The paycheck should be for living expenses, IMHO.
> In Silicon Valley, 75% of founders pay themselves less than $75,000 per year and 66% pay themselves less than $50,000 per year, according to the data.
These numbers are lower than what I would consider reasonable for a founder [1]. You certainly can live in the Bay Area on these salaries, but it means spending more time thinking about how and where, possibly having a longer commute, and possibly dealing with poor roommates. All which waste time, time which would be better spent on the start-up.
[1] For an SF-based single founder, I'd consider $80k reasonable. Higher if (s)he has college debt to pay off.