The sale success of the Steam Deck proves you wrong. The PC is the strongest platform for exclusives because most of everything ends up there eventually. The Xbox has no exclusives anymore, Sony is publishing everything on PC eventually. Only Nintendo remains as never publishing on PC. If you are flexible about your choice of multiplayer-only titles (if you're even interested in that type of things) then the Steam Machine is the best console.

Sony's in trouble; their crown jewels are all on PC right now! You can buy a Steam Machine next year and play all the Spider-Mensch, the Lost Hose, the Ghouls of Yo-Kai!

The Steam Deck has sold only 4 million units in 3 years, which is a rounding error in the console market, not a huge success. The Switch 2 has generally been considered a failure (due in no small part to a serious lack of interesting exclusives at launch) and has still sold more than 10M already, while the Switch sold 154M units and the PS5 has sold 84M.

DotA isn't AAA tier? It's the #2 game by a big margin on Steam. And also League of Legends is just as big. How are these not AAA tier games?

LoL can't be played on the Steam Deck. This is common among the top multiplayer games due to anticheat.

It's almost certain no one bought a Steam Deck primarily to play DotA, and it remains to be seen if any has a meaningful impact on the Steam Machine, but I doubt it.