A lot of people now want to use their browser for far more than that and browser technologies are evolving accordingly. I'd suggest it's been quite a while since browsers were meant to be used for nothing more than browsing html files.
No. People want a way to quickly use new software. It's just that the easiest way to achieve this today is providing applications via the browser.
Therefore in terms of the expectation of a majority of its users, it's not accurate to define a browser as something for looking at static html documents.
Not to say there couldn't be a different something for this - java applets, flash etc have all tried and failed to remove this from the browsers functionality to a delegated function - but at the moment there doesn't seem to be a viable alternative.