We're in a world of APIs and de facto protocols now. The bulk of the interesting communication at this point is about data. REST over HTTP provides a decent mechanism for interacting with arbitrary nouns. Anything significantly more structured would, I imagine, essentially be an exercise of modeling a particular domain of data. With rapid innovation, it becomes difficult to codify a particular data model ahead of time, so we end up in a world of RESTful APIs, some well-documented and some not-so-well-documented, and, when one emerges as the winner, it becomes the de facto protocol.

That said, the walled garden approach of all platforms today (especially Apple) certainly endangers future innovation. Though, I see that as a content delivery problem, not a protocol problem.