Perhaps the difference now is that the music shown in those commercials where they succeeded for the bands had a sound that worked for a larger amount of people. If you listened to the top 40 type of music at the time each of those commercials came out, how many of those indie bands were playing something quite different vs just playing something similar to what was already on the chart?
Thus perhaps whoever was finding the bands before knew what they were doing, and the more recently picks were not.
One other data point. I just picked up the deadmau5 album 4x4=5 off google play music all access for two reasons. It was something different then what I already had but sounded good. And google had it for free. (they've had free albums I didn't have an interest in, so free was not the only factor)