We know for a while that those numbers were inflated... And imo, this latest update being a major flop (in my books) didn't help TF2's case. Sure, we got a lot of fixes, but given that it took more than a year for a major update to hit, this was no gift to the player base. And while a lot of requested bug fixes were put to the side, we got a lot of unrequested "improvements".
Until Valve gets off their pedestal and starts being less restrictive about a lot of things* and letting we only play the version of the game they want us to play, things will just go downhill (sure, it's their product, but it's been on our hands for many years, and a lot of popular features have been stripped over the years).
* I.e. mods, sprays, quickplay, community servers etc. A few changes had some reasoning behind it, but didn't warrant being stripped/blocked. Just improve on it. For example, TF2, just like TFC and HL, have some default sprays. So Valve let us customize them. Then the porn/furry sprays started to appear. So no more sprays on Valve servers. Overwatch has official sprays, and they're really high quality, like everything else. So, in typical Valve fashion, more stuff for them to pour into cases and get their $$. And hire a bigger dev team (as if money was the issue).