Companies need to make money. High performers will go to companies that make tons of money, even if relo to Sahara is needed
The companies that make lots of money then end up being softer & more extravagant with their employee (ahem, GOOG and a lot of Mag7/FAANG) until some equilibrium point where they're so soft they lose their edge.
Then a new up&comer rises and the cycle repeats.