The demand explanation makes sense. It's also that the critic-publisher power dynamic is so lopsided toward the publisher. I don't think outright paid reviews are common as /v/ thinks they are, but publications are definitely spoonfed information, exclusive and otherwise, under the expectation of favorable coverage.
I like to think that Roger Ebert was not beholden to any movie studio (he was accused of being beholden to ABC on a few occasions). He was both a critic and reviewer. He was mainstream (what movie is good right now?) and intelligent (why is this movie good or bad?). He was also good at finding where the mainstream and the intelligent merged.
Another reason the GameCritics brand of criticism may not be in demand is because criticism is perceived as something bad. It's bad to criticize. We grow up being taught this. A lot of people in the mainstream don't want to play 5/10, three star or 75% rated games. Those are some of the most fun games games I've ever played, especially those that generate a wide variation in scores (and more importantly, opinions).
I like Gather Your Party. I am usually weary of any publication that calls themselves honest (I'll be the judge of that), but here's an example of some thought-provoking material.
In the comments I suggested that video games don't necessarily need stories.