Noobs quit crucible because they don't like being stomped. The number of sweats stay the same or increase. As time goes on the sweats make up more and more of the crucible population, thsu they encounter eachother more and more. Consequently crucible becomes sweatier for them. There is no SBMM, just a bunch of noobs quiting crucible. A pubstomp type crucible is never a sustainable model, especially in a PVE main game like Destiny 2. The only reason noobs haven't outright left crucible is because Bungie locks good PVE weapons behind pvp. Crucible will just get more and more sweaty as time goes on, and eventually the sweatlords might be back to square one where all they encounter is themselves. That is unlikely though as long as Bungie keeps artificially populating their crucible by locking good PVE weapons behind it