The Cycle of SMG4 Youtubers - and Why Some of Them Quit

If you've been sticking around the SMG4 community for long enough, you may have noticed the slow depature for some of those UA-camrs, like Machroma and CiblesYT. Why does this happen, what causes this to happen, and is there a pattern for why these SMG4 UA-camrs are leaving?
Maybe, a cycle...
also this video is really poorly edited because i was very busy at school this week with assessments