IMO it's down to the fact there is amybe a 5% Casual-to-95% Sweat ratio in Crucible now, because both PvP specifically and the game in general are a dumpster fire. So almost no one is playing, and those that are are the die-hard lovers of the current state of D2 PvP (and poor sods like me who still need Season Challenges....).
Although, yes, there are also far too many actual cheats because Battleye is worthless (and Bungo still think Marathon will somehow be ok using it....)!
Look the game has been crap for years. No matter if its 50/40, 90/10, 95/5 its always so horrible. Bullets do nothing. I had an entire match where the same dude would get hit 99% hp off his health and magically 9 times in a row they have 1% hp left after every engagement. I cant take it any more. Between the bugs, cheating, exploits, and whatever other shenanigans its just unfair.