I forget if I've pointed it out before, but....

The Grammys reward, almost solely, record sales. There is very little quality judgement involved. In fact, there's not any real way for them to do anything else. There are so many albums released in any given year that even the person who listens to the most probably only hears 10% of the output. That being said, the only artists that get enough votes to be nominated are those that everyone has heard. That is, the ones that are already best sellers.

That being said, I don't really understand why the new Metallica album sold as well as it did (it truly is crap), but it did nonetheless. I know one person who liked it, though.