Alright I watched the video and besides it being what you'd expect from a typical LTT video, I don't see anything that'll get me to raise a pitchfork.
He's talking about SteamOS from the POV of the average gamer, who he calls "Joey Mainstream". I'm starting to wonder how many people on this site regularly talk to none Linux users/gamers?
I also brought this up in another post a while back, Your average gamer doesn't care about open-source, privacy, software, corporate overreach, etc. They just want software OS made by a corporation they trust. Most of these people probably only know of Linux from memes about needing a PHD to install a web browser.
Also should point out I personally do care about all the things I mentioned before. And I think mainline/non-SteamOS Linux is already great for gaming. I'm just pointing this out as the general consensus from most people I talk to who a line with the "average gamer".