None of the product managers in those companies you cited are paid to stay the heck out of features that's already working. They are paid to scale those feature

None of the product managers in those companies you cited are paid to stay the heck out of features that's already working. They are paid to scale those features, add more usecases and re-shuffle the design so that all the latest use cases are captured. This means the softwares are evolving at a pace the industry hasn't seen before. And there's another dynamics at play. Design community these days are infected with apple driven thinking, treating users as stupid and worrying about decluttering. The focus instead should be on how will a design scale for known unknowns and unknown unknowns? How will complex usecases compose well with simple usecases? What happens when an unknown error happens? These are stuff that nobody seems to worry about in the UI design sense, IMO.