Yes they are. There are also 'total conversions' in the gaming community where a game had nearly all of its assets replaced to become a new game. The pieces are all out there, but they haven't yet combined into a single thing yet.
We often think of ideas as being these amazing things that spontaneously spring into existence, however they are more often the amalgamation of a bunch of things that have emerged on their own and then contextualized in a way that unifies them into a cohesive whole. My thinking is that distributed game economies are going to be such things.
One of the early things about WoW was the emergence of "gold farming" which exploited legitimate game tools (questing, mailing gold to other players, in game transactions) and demonstrated you could earn real money off players by selling them virtual goods. Personally, I think that was the point when game product managers said, "Hmmm, that is money we could be making" and the "freemium" model was accepted as a legit model.
They still keep 'game flow' and 'game assets' in house however, but the curated app store model has shown business people how you can let third parties make stuff and then give them a platform to sell it and skim the profits. When you combine these two models in games you get this new thing.