I see the difference in that "enshittification" is what the platform owner does. "Glossification" is what the users do. Of course both are closely related.
To elaborate, with an example: ebay has once been a platform to find things non-professional people would sell from their attic on the cheap, as an auction. Then professional sellers came in, first with auctions (either more expensive ones, or by using sockpuppet accounts to drive up the bid). That was glossification. ebay then of course went through enshittification, with fixed-price offers, selling preferred spots, etc. But interestingly, they currently seem to try to revert some of that, because glossification and enshittification affect their bottom line, so now non-commercial sellers get zero fees and their own classifieds' platform
Yeah, they're two related yet distinct issues. Take Medium or Quora for example. The whole 'login to view any content at all' issue would be enshittification, since its the platform owners trying to screw over users for their own benefit. The flood of low quality, crappy articles and answers by people trying to make a quick buck would be this other phenomenon, since its the users trying to make a buck at everyone else's expense.
To elaborate, with an example: ebay has once been a platform to find things non-professional people would sell from their attic on the cheap, as an auction. Then professional sellers came in, first with auctions (either more expensive ones, or by using sockpuppet accounts to drive up the bid). That was glossification. ebay then of course went through enshittification, with fixed-price offers, selling preferred spots, etc. But interestingly, they currently seem to try to revert some of that, because glossification and enshittification affect their bottom line, so now non-commercial sellers get zero fees and their own classifieds' platform