My impression is that it's mostly a matter of inertia. On the technical side I don't think any individual part is unsolved or even hard but technologies and the

My impression is that it's mostly a matter of inertia. On the technical side I don't think any individual part is unsolved or even hard but technologies and their applications keep changing (e.g., mobile) so it's not possible to create one unified, elegant framework without it being obsolete immediately; the alternative is that we incrementally evolve the existing mess ... Furthermore, perhaps there's also an element of companies making their competitors' lives more difficult by not embracing standards introduced by others.