Another thing I noticed at these top-tier companies is an alarming propensity for hiring people simply so they will not be hired by another company. They end up on these awesome little make-work projects that never see the light of day
I don't think it's just to keep them from other companies, it's that the returns on the projects that do see the light of day are so huge, that it makes sense for tech companies to have 10 of those and discard 9.
I get your perspective, but… I saw tons of guys in “research“, “fellowship“, and “architect“ positions who were achieving nothing useful for years at a time.