Cheaper, simpler, sufficient technologies typically win over complex ones. Email over complex 3D chat. Async over sync. SMS over voive. Image sharing. FB over blogs. Mobile over fixed. Complexity (in the eyes of the user) is virtually _always_ a loser.

And discretely monetizeable chunks -- ads, music sales, monthly services, frequent sales. The dream of a ubiquitous, always on, universally accessible information stream of the 1950s - 1980s seems not to be compatible with business necessities.