I did a few hundred keys in each season of Shadowlands up to about the +25/+26 level and almost never saw this. Sure there were tons of failed keys in that mix due to missed interrupts or mis-pulls and a million other factors, but in my experience there are an equal proportion of terrible healers and tanks as there are terrible dps.
In fact, many WoW players vastly overestimate their own skill and knowledge of the game. Especially the ones who have been playing for 15+ years.