It's an interesting question that I've pondered as well. I think that in general it's due to the proliferation of media. It's opened the doors on everything. We have so much more access to everything than we used to, so I think it's natural that there would be more of the louder voices, so to speak. The louder ones tend to get recognized in a sea of voices, not to mention get money thrown at them.
Indie artists have always been here, but I think the internet's given them a new avenue that made it easier for them to get exposure, but the downside being that they now have to compete against the louder voices to get noticed. I've discovered many great musicians over the years that have struggled to not get drowned out. Of course that's been true in the past too, but I think even moreso now. The expansion of media has become a double edged sword.
On the other end of the spectrum, there's a band I really liked that I've wanted to see for quite some time. They became extremely successful and popular touring the festival circuits, to the point that they became too expensive to book in their home country. That touring took its toll and they broke up, and the last I've heard is that they're reuniting with the original lineup and also recording a new album.
If you think about it, it's not only true for Music, but other forms of media as well. It's become so much easier for people to show off their works. For example, digital cameras have exploded in popularity and there are some that have become really good at composing shots, and not having to worry about wasting film. There's more experimentation going on than ever before.