I agree with you in the case of NiN and Radiohead. But while OK Go did have one single that charted via traditional means, their last two big successes came in large part due to the popularity of online videos.

The videos for "A Million Ways" and "Here it Goes Again" were fairly low budget affairs that were likely within the range of an independent band.

While I'm sure that the label did provide some help, it seems to me that their breakout success was largely achieved in ways that can be duplicated by a talented unsigned group.