When did leaving mid-game become the norm in zombies mode? It's pathetic.

I stopped playing early into Black Ops 3 due to wifi issues, after being heavily into black ops 1 & 2, and just never got back into Call Of Duty until a buddy of mine told me how wild the zombies mode was in Black Ops 6. Having played alot this week for the double xp, I ran into a pattern that bothers me to no end. In so many lobbies, once someone got down, they were just quitting if they weren't immediately revived. This was never a thing back in the day, and it's one of the most infuriating things I've encountered so far Black Op's 6 Zombies.