@sauced284 I have 9,999 hours (a lot of time I just turn off the TV and walk away because I don't play anything besides Smash) I have well over 3,000 hours of in-match time though.
I will say, from switch lite experience I can tell you that putting your switch in sleep mode counts as hours. Maybe this guy just uses sleep mode a lot.
There are people who open arenas either to train or stream and will just leave them open to let others play. It will cause those who haven't actually played that often to have crazy hours