Obviously this means one has to be earning that much for 15+ years.
Still, if you reach staff-level at 40 years old, you could have $25M at 55. That's pretty amazing. But that requires lots of luck. Most people never make it to staff-level. I never did.
Another thing: People at FAANGs usually ride the stock up and get way more than 7% per year. I'm embarrassed to say that I sold a lot of MSFT stock at $30 in 2011. Today (~15 years later) it is trading at $530.
This seems...high. The levels.fyi data for 68/69 shows them maybe crossing 1M, and the highest available data point at a bit under 1.5 mil. Staff engineers at FAANG are not making 1M a year except in cases of significant stock growth. 700-800K is more reasonable. The AI labs pay a significant premium, yes (2-3x!).
My math on it was basically "I can work for 10-15 more years and retire meeting my financial goals, or work until my 4 year grant at an AI lab finishes and meet all the same goals, with more interesting work".
That would be what I'm trying to avoid.