Don't the majority of FAANG engineers cap out at Sr. Engineer and that's a title you can get just a few years out of College? So are +/-50% of Google engineers stagnant?
For companies as prestigious as FAANG, I think such rules are thrown out the window. Assuming you choose to leave, you probably will have no shortage of companies asking you to come work for them.
It's a valid point. I should have specified that I meant stagnation skill-wise, not career-wise.