I've liked a few of this guy's videos before, but he comes off as an unhinged lunatic in this one.
The video is basically just him trying come up with an excuse for Deus Ex: Mankind Divided not being as successful as Human Revolution because he thinks it's a good game. His excuse is asinine and unrealistic, though. Seems pretty unlikely to me that "gaming journalism" think pieces attaching the label "immersive sim" to the game are what killed interest in it, and a lot more likely that the game's cringe-as-fuck theme and related marketing is what buried it.
It also just wasn't even as good as Mankind Divided, in my opinion. His opinion about Prey 2017 sucks, too.