I think you are right on this. Even since I've joined (June 2017) there seems to be a lot less spam and "follow for follow" comments. Maybe it is the posts I'm reading, but I just don't see as much junk as I used to. This will probably go in waves, with some time periods being worse than others. Overall, I think that people will give up. Being social can be difficult and the people who are here for a quick buck will probably stop posting within weeks after joining.