Yeah my current feeling is that once I had double digit millions earning further money would be pretty meaningless to me, and the difference between 'large salary' and 'even larger salary' would be even more meaningless, but who knows maybe it really would change me. I kind of assume people like this are primarily chasing the most interesting/impactful work though.

The problem with this belief is that it implies that all of bigtech is massively overpaying for top talent who would happily stay on for pennies. While bigtech overpaying talent is more plausible than any other bigcorp doing so, it's still rather unlikely.