Thanks @archsimkat you saved me the trouble of writing that.
@phong, two related things in response. The first being that rating is a bell curve and it doesn't make sense to add a huge number of people to one extreme end of the bell curve without padding the rest to maintain some reasonable average. Hence both my comment and presumably FTX's comments about there needing to be a lot more "average" players for there to suddenly be 1k top pros.
For the second, let's ignore what I just said and pretend it really just is 1000 new top players. This ties in heavily with what Arch said and what I was starting to type up before I saw Arch's post, but top pros bring in a lot of new people and do a ton for community engagement. What do a lot of pros, including top FAF people do? They stream. Streaming drives engagement and awareness for the game. Streaming gets new people interested in the game. 1000 new top pros means, what, 100 new active streamers potentially? That would be huge for FAF. It also means far more tournaments, and far more competition in those tournaments. Which means more official streams that draw in more people. Which in turn makes the viewership goes up, which in turn means more people get exposed to said streams that might not have been otherwise exposed to it. There's a reason most big games have a vibrant competitive scene, and why many times they'll start to decline as the competitive scene declines.
It also means more casts get made, and additionally casts consisting of actual high level play. Again, refer back to Arch's post regarding this since that's identical to how I feel. For me, watching Yudi in particular was huge motivation for me to get better.
Edit: I'm actually not sure if I'd be getting back into playing some FAF right now if not for Farm's stream honestly. Watching it makes me want to play, and also shows where there are some high rated games going on. Having more active and skilled streamers is huge for any game community.
As a side comment, I play a bit of Apex, and while I'm over a decade past my prime on FPS games and am complete trash, I'll watch highlights of pros or top streamers and get motivated to play as a result. I'm reasonably sure that both myself and my irl friends I play Apex with wouldn't be playing it if not for the competitive scene and the streams + highlights from it.