No, my problem is with the stupid amount of people who treat Steam like the end all be all of PC gaming. That basically gives Valve control over the entire platform.
That's not Valve's fault though. Saying they are overlords almost implies some sort of plot to control the indie scene on their part.
Steam is successful because they were one of the first, have a very extensive catalog and provide convenience features that no one else does like autopatching and cloud save. I imagine the achievements and social aspects are a draw for people too, though I've never much cared about those personally.
Other than the early advantage, there's nothing really stopping the competitors from doing the same.
They are pretty good about selling and promoting indie games, I will give you that. Beamdog too, but they are a small outfit. Direct2Drive and Impulse have some indie games but they never promote the damned things. Their front pages are always AAA sales and pre-orders. Origin wouldn't touch anything indie with a 10 foot pole, unless of course EA bought it out for a hefty sum.
I'm not sure who jumped in with greater enthusiasm, Steam or GG, but either way the best thing to do is buy directly from the developer.
In a perfect world I would love to do that but if you want to have more than a few games it's just way too much of a hassle to keep track of them all that way to remember what game you got where, who's got a patch etc.
I do think that alternative ways to promote indie games is a good thing. The Humble Bundles have been pretty successful in doing that I think. I don't know how much money the developers actually see from it, but it does get a lot of attention and generate money for charity so it can't be that bad.