Well, in case you didn't get the memo, the definition of World Wide Web has changed dramatically since the 1990s.
World Wide Web is no longer about seeing pages to present you with information. It's about running applications to give you functionality. This effectively turned the web browser into a not-so-thin application client.
I believe this whole thing happened because Microsoft had control of what gets installed on desktop for a long while, and the only application-client technology installed on all machines was a web browser. If all machines were shipped with an X server or a VNC client or some other application-client technology, maybe things could have been different. But we are where we are, and because of that features like Canvas, HTML5, WebGL, NaCl, very fast JavaScript JIT engines get added to the browser to make it more efficiant APPLICATION client, not a page browser.
--Coder