Primarily because there's not much to talk about. The game was barely out of the door, and it's still a tech demo per-se, not a proper release/live build. Even the updates were sparse and few so you can't amass much engagement if you don't have anything to show for it.
I don't agree that Mass Effect is dead, but it's just not culturally relevant anymore like it used to be. However, Architect's games require a power dynamic, and I don't recall any other recent IPs or something like BG3 where it could fit that theme.
The issue with Mass Effect is that it's pretty much over. The Remaster is already 4 years old and it's not getting much traction, most people that bought it, were old fans that couldn't play it on consoles anymore, hence why in some stat announcement Bioware made at the time, something like 80% of sales were on Playstation. Even then, most of the new people that bought it and played it, didn't engage with it like old fans did, that had to wait 2-3 years between releases. People binged it and moved on.
The other thing is that the Trilogy is over, and the cast is retired, so there is not going to be a resurgence of these characters, even with the next ME, because they won't be in it, and if they will be, their 5 second cameos won't sell them to a new audience. And then, there's no way a new cast of characters by this Bioware are going to top the trilogy cast. So, while not dead, Mass Effect has nowhere to go, and no way to make a come back. These characters will not be relevant in any way to younger people in 2-3 years. None of them will care how anon killed trillions of his children, jerking it to Tali's 3-toed feet, 20 years ago.