Back in August TFT has seen a major dip in viewership on sites like Twitch where in the last 30 days alone TFT has lost nearly 60% of its total viewers and is broadcasted nearly 50% less than it was before and looking at several charts, this doesn't look like it'll change anytime soon as TFT has simply been on a steady decline.

Though if there's any good news to come out of this it's that following Riot L4T3NCY's word regarding RGM, a total dip in popularity in TFT might just be the small spart Riot needs to continue supporting other gamemodes again.

Sources:
https://sullygnome.com/game/Teamfight_Tactics/30/summary
https://esportsobserver.com/top-twitch-content-august5-11/
https://twitter.com/RiotL4T3NCY/status/1166040088259641344