Dunno about "everyone," but my friends have all quit because of issues regarding installation--I don't mean to sound like I had a lot of friends lol but the few that started the game with me couldn't get the game to work consistently, even with the tweaker. Anyone making the tweaker seem like a universal remedy is ill-informed. My buddies are no strangers to the inner workings of Windows either, so I can understand why the install/uninstall issue would get some people to quit.
Personally, I've also been playing less and less each day haha. I made some friends and it was fun farming with them, but they haven't gotten on recently and I bet that has had an impact on my willingness to play as well. It also doesn't help that the extremely small chance of actually getting a nemesis/slave weapon to drop and selling it will only help you with a fraction of the cost of buying any new fashion items…and this is coming from a male character's perspective haha we only need to worry about accessories since the outfits barely cost a dime.
There hasn't really been anything driving me to play the game after maxing classes and skill points, and that was after the last ABR event a while back. I mean I'll get on for maybe an hour or two of ultimates after work if I feel like it or maybe if a good urgent quest is up, but as of right now, the only consistent fun I really have with the game in its current state is Black Nyack.