> Its best for the remaining people too.

It sure doesn't feel that way to me, as someone who has seen lower-performing (I'd hesitate to label them under-performing, these people simply never should've been hired into the role they were put into in the first place, but those are anecdotes for another time) be PIPed and ultimately let go, because all it means is my own workload is going to go from fucked to even-more-fucked.

That’s a bad management issue. Your workloads shouldn’t be drastically impacted by how many coworkers you have. If you lose a coworkers it’s your managers job to rebalance the roadmap or negotiate with other other managers and their manager to get a up to speed backfill.