It is also possible that the "poacher" has such a ridiculous amount of money at their disposal that they're able to suck a talent pool dry with "so-much-money-you-can't-refuse" offers. I think, however, that enough employees are getting wise to the fact that a FAANG offer isn't an automatic "yes".
People do turn down offers even if the money is crazy high, especially older folks who have gained some control over their career path, have job-satisfaction, and don't want to stage-dive into a competitive hellscape of Type-A 20-somethings.