> These gamers presumably want reviews of what is / isn't worth their time.
They want reviews that the can trust to predict their experience, and trust in the games media for that is (for a variety of reasons) very low.
> Sure, as you mentioned, there are individual YouTubers or Twitch streamers... but one streamer doesn't have nearly enough time to review all the games that come out.
So? No one has time to read/watch reviews of every game that comes out, either, or to play all the games that come out; if they can find a stable of trusted streamers that combined give reliable and timely impressions of games so that they can find a sufficient number worth playing and mostly avoid wasting money on duds, they don't need reviews of every game that comes out, and they especially don’t need that at the expense of reliability.