Decentralised music subscription services

While Jim Griffin's plans for compulsory licensing for online music are beginning to make some headway in political and music business circles (it's a good idea at first glance—although hard to define what should be covered by the license—but the level of network monitoring involved turn it into something much more undesirable), Lucas Gonze has been making some points (on Pho, but reprinted with permission) about subscription services that bear repeating for their insight:

What's interesting about this question is that it goes to an assumption about subscription services -- that one vendor can ever provide a one stop shop. It is much more internet-y to work on systems that encompass multiple vendors. Anybody who wants to be a vendor should be able to join in the melee. That's a well functioning market.
Sony's web site, for example, isn't driving anybody mad with desire, but it doesn't have to. It's one site among millions and it works just fine. So why not Sony's subscription service too?
It's not possible to have all the music known to man in a subscription context without finding a way to make a decentralized set of subscription services from different entities with different catalogs interoperable.

I'd much rather pay a bunch of subscription charges (maybe amalgamated into one over time) for unlimited access to a set of distributed catalogues, each reporting usage and paying fees to a central agency, than pay a flat rate internet fee and have all our traffic monitored (see also: Phorm).

Note that I'm talking about subscription to buy, à la eMusic, rather than subscription to rent.