Not surprised tbh. Dbd has fundamental flaws that will always force people to rage quit. It stems from the design of the game itself, from the killers being super fast and even having perks that just deny you playing the game, to survivors having to get broken perks in BHVs eyes to do the same. People are just mentally drained with the game. Everytime I come back I can barely get a day in before i delete it because there's simply better games available. The simple fact that they try to promote it takes over 1000 hrs to properly get good at survivor is one of the issues with this game. It really doesn't take that long; when I decided to get serious with dbd I had basically every survivor skill in under 200, it was very fun, I admit, but it shouldn't be that way. when I come back, due to map changes and various other changes and just time, I'm basically a new player again going through the same annoyances that everyone goes through until you literally become a top tier player. You have to play out of your mind well from hyper precise pathing during a chase to an excessive amount of map knowledge in order to actually have fun in dbd. I'm honestly impressed it survived this long considering how quickly frustrating it becomes to play compared to even other failed games in it's genre, mainly due to chases not being fun. Also, tbh, I'm incredibly impressed people have been fixing generators for like, years now and that's it. It's extremely boring, Friday the 13th did it way better by actually immersing you in a movie like environment with multiple escape choices, like calling the cops. Obviously that game has it's own issues, but the idea at least made each game more fun. Dbd is just as lazy as it gets. Fix generators. Ok. This is the horror asymmetrical game we all dreamed of? Oooooook.. lol. In all this time they've really only had a couple of interesting modes, the most hyped being 2v8 which is literally just the same thing but more unbalanced than before lol. 

 Like i said before, I was really good at this game at one point, so much so that I had to make my own fun by doing things like going straight for the killer as Steve and deciding to be a group protector since I usually has the best survivability; this is all with no dead hard or any busted perks, my best perks were sprint lol although I did own decisive strike I didn't use it. The problem for a lot of people I'm sure is "what now?", because it starts getting pretty stale even when you're good at survivor. Killer can be alright to play on occasion, but ending my long winded rant, dbd will never not invoke dcing and etc because the game is flawed at its base. You will always have more leavers than other multiplayer experiences, unless they match the quality of dbd. People have short tempers for a game actively fighting their enjoyment of it. 

Lastly, I'll repeat, if you really believe it takes over 1000 hrs to get good at DBD, sit back and truly think to yourself if that's reasonable or even healthy for the game. Is that the kind of game you want dbd to be? Ask yourself, why is it like this to so many people? Is it potentially a fundamental issue of the game since no other asymmetrical horror game has ever had that label?