It's a shame that bay area housing prices, which higher paid tech workers already struggle with, are even more of a burden for Facebook cafeteria workers, who make less money than many of those they serve every day. Thankfully, since your year-old article, Facebook cafeteria workers have unionized. I hope it's helped.
Still, it's unlikely that food service and retail workers in these cities are having an easier time making ends meet. The article you linked acknowledged that the cafeteria workers were making well above CA minimum wage - do you think the same can be said for all the restaurant/shop employees in the bay? Is there a reason we should be more concerned about some service industry employees over others?
Do you have a source for your claim that people are cheating on their income taxes to the tune of thousands of dollars a year?