I love and stand by Steam, but all that needs to happen is that Gabe Newell retires, or the company is purchased. Once that happens, kiss it all goodbye. (And probably also kiss awesome Linux compatibility goodbye as well.)
It's a similar situation to what happened to the fallout series. Bethesda took a stab at it, but, if you loved fallout 1 and 2, nothing they made really felt like fallout, even if they were good games.
Not quite on the level of duke nukem forever, mainly because apogee was mismanaged at it's very core, and valve, well, hard to say that it's not managed well.
The thing is, making a good game is not really necessary here. They could make a mediocre halflife3, get slaughtered in the reviews, and still make a ton of profit, Gaben just won't do it because he doesn't want to go out like that. Understandable, but, it's mostly his fault that he's in this situation. If they released 3 a couple years after the episodes, they could have continued that incremental release pattern more or less indefinitely, it's just that at the time they were focused on other things (that turned out to be more profitable) and by the time they got back to making games again, it was too late, too much hype to live up to, so on the shelf it goes.
I just don't think he cares. half life 3 can sell 100m copies at $70 a pop (so, 7 billion dollars in raw revenue before various fees) and it still wouldn't touch Steam, which has estimated 9 billion dollar revenue in 2022 alone. Maybe it'd make even more as a service game or by integrating steam marketplace stuff like TF2/Counterstrike, but the number of games that make steam level revenues year after year can be counted on one hand.
For some reference, Fortnite hit 6b in 2022 and 26b in 6 years leading up to 2022. very strong average of 4.3b, but fortnite's game team is twice* the number of employees Valve has in the entire studio. A lot of labor needed to maintain one of the highest earning games out there, and Steam still comes out on top in raw revenue.
(I can't find exact Valve numbers, but LinkedIn still lists them with "200-500" employees. And since Epic has at least half of its 4000 staff on Fortnite...)