We seem to be dividing the internet into two kinds of endpoints: clients and servers. Servers are "where the code runs" and clients are mere consumers. Though the network is a tool, the current practices of network software development are putting that tool only in the hands of those who control the servers. The computer on your desk should be considered just as important and just as powerful as the servers that run your favourite websites. It is not a mere consumer endpoint. It is capable of so much more, and furthermore, that is the point of having such a machine in the first place. If the only program your computer ever runs is a web browser, then it's not a real computer and you are nothing more than eyeballs to online advertisers. That's called television, and the web does not need to be more like that. Why would we want to turn back to that model of centralised control?
Mokalus of Borg
PS - It's interesting that Google's Chromebook project is pushing towards browser-only uses.
PPS - I suppose it makes sense for Google. Their revenues come from online ads.