The "walled garden" networks will always strive to find their value in lowering the barrier to entry for new participants on the web. Facebook makes it super easy to share your photos with your family and friends and passively update them on the minutiae of your life. Twitter does the same thing to large degree in a more public fashion. Tumblr, Instagram, Pinterest... all of the same zeitgeist: user experience.
But the cognoscenti are certainly aware that the web is the sum of its parts and walled gardens are antithesis to participation within its ecosystem. However the problem is and has always been participation: there is no single sign-in, no simple user experience, no common parlance for the mainstream to absorb. We got about as far as blogs and stopped there once MySpace, Facebook, et al took over.
I'd prefer a return to the roots but I think we'll need software and services that provide a better user experience and product-based focus rather than the service-oriented approach that has become popular.