It works, yes, but with great effort. Think of all the development time spent grafting applications on top of what is fundamentally a document delivery system.
It's hack upon hack, kluge upon kluge.
Example: Do you think HTML/CSS/JS is the right way to develop a user interface for an application? I don't.
No, it hasn't. The web is a terrible, hacked-together mess. Things break often and catastrophically. HTTP 2.0 is layering on more hacks instead of trimming the fat.