I see all of these services as at a cross-roads:
either one will cross the critical mass of getting enough paid subscribers to make up for tiny margins or one will change its model to percentage royalties by convincing the payees that it will attract enough subscribers to make this worthwhile.
The two cross-roads intersect after they split by the tree of basic survival, because the achievement of the critical subscriber base, as yet unaccomplished by any, will make both models sustainable.
I am not clear if either model could succeed. I am fairly clear that the efforts by current payees to try to get raises in both direct and radio-type streaming royalties will be likely to kill both the services, the Pandora-style services and whatever is golden about the streaming egg.
But we’ll see.