Browser sandboxing currently seems to work, users vaugely have a sense of how to avoid hacking on the web. A new protocol would have a lot of catching up to do

Browser sandboxing currently seems to work, users vaugely have a sense of how to avoid hacking on the web. A new protocol would have a lot of catching up to do, and would probably just be... a modified browser, because browsers are amazing at GUI stuff. Browsers as OSes work fine, aside from the fact that all the advanced features aren't real standards, and everyone other than Google tries to kill them, so you can never be sure what's going to get deprecated later.