There's no breaking point, just ever-increasing inequality as an inevitable consequence of structural factors. Feudalism persisted for centuries, and it can again.
You'd think there would be a breaking point somewhere around "we could pay 25% less and still attract top talent to relocate to literally anywhere in the Western world". The cost of living in the SF bubble has long since passed the point of being insulting and the salaries being commanded by those who are driving the continued growth could go so far in other major metro areas that most employees would think they're living like kings even with such a paycut.
Even in the feudal era, early landowners didn't generally pay artificially lower taxes than later landowners. What we have with prop 13 is worse than feudalism.
