But their payout is based per stream, not per track, isn't it? At amounts that still exceed that of radio?
"For a 99c sale of a track on iTunes an indie artist gets 70c. At the time you need 140 Spotify streams to make the same 70c." (Source: http://www.spotidj.com/spotifyroyalties.htm)
These figures are hardly comparable with piracy, and for an artist with a reasonable audience, should more than exceed the $.918 average royalty for a song per unit sold that record companies provided in the era of CD sales.
While exact numbers aren't disclosed, I've seen a $0.004 per play royalty thrown around enough that it's probably at least ballpark.