So here's some history for you, that due to what you wrote is kinda funny;

First, note I have insane hours in PoE, but haven't actually played it in years, so I can't comment what it's like now. I had 7k+ hours since beta till about Betrayal. I haven't played it since.

Anyway, PoE is one of the only PvE focused games, that grew in playerbase since it released.

Like, it's one of the only games that is not player vs. player oriented to increase player numbers year on year there's ever been since 'games as a service' etc. became a thing.

The reality is, and this is all games; PvE games only decline in player numbers after they release.

Idk all the business of it, but it's real. Chris even talked about this point in his GDC talk I linked in the initial comment.

If it's dying now, sure, but that game is old as balls now. It's been out since 2013, and it grew in player numbers year on year every year/league and was still so when I quit.