Galleries need to sell stuff. Generally, photography is a tough sell. Unlike drawing, painting etc, it is difficult to get the public to see the monetary value in a photograph, because the "hand of the artist" is not obvious.
Please note this post is not meant to imply blurry, grainy or "badly" exposed pictures are inherently any better or worse than straight work. I'm just trying to put forth a possible explanation for why we might find more of this type of work in galleries.
Michael, that's a great explanation for what many seem to observe here, but it also confirms that not everything we see in galleries will pass the test of time. Which isn't new either, AFAIK Picasso burned his early paintings to keep his room warm, while galleries were full of less worthwhile stuff that has long been forgotten since then.
Trying to be the best of whatever I am, even if what I am is no good.