There is a place for both: Streaming services and DB/SN sites. they don't have to be the same.
I even hope for more segmentation (and interoperability) in the future: Companies that only provide the raw music. Others that build the UI/UX (players...) and still others that provides additional services (Social networking, Data related...)
Last.fm lost not because it is too genuine (CBS is one of the largest media conglomerates) but because it got lazy and failed to leverage its data to create more value. The truth is people are just as Lazy when it comes to music (organize, discover…), _so I wonder how much you can really grow in this space.