I've thought about this a lot as well and don't have a good answer. My best guess is that this comes about via group dynamics (so and so is hiring and we should

I've thought about this a lot as well and don't have a good answer. My best guess is that this comes about via group dynamics (so and so is hiring and we should too!) and external investor pressure (you should grow faster says investor!) that forces the hand of executives who know deep down it's gonna go south eventually. Also we have to understand that sometimes the callous decision to do this deliberately (better to hire fast and grow faster now and then lay off the bottoms X%) is made. In my experience in tech its hard for me to see how that makes sense considering the resources + time it takes for a new engineer to become productive but perhaps in FAANG level companies the onboarding process is good enough for that to work at scale i.e. getting 0.5x of a new engineer for 6 months is still better than the costs to train and pay em for that time.