Earlier quoted context omitted.
I think the culture of tipping waitresses persists in those states because these are relatively new laws and don't apply in most parts of the country.
I’m not sure California has ever had a tipped minimum wage that was lower, but not in the past 3 decades at least.
https://www.dir.ca.gov/dlse/faq_tipsandgratuities.htm (which is returning NXDOMAIN right now for some reason)
The Federal DOL page says minimum wage for tipped workers in CA is currently $15.50.