How would that free up bandwidth? If I'm accessing the web, I'm using bandwidth no matter what - be it large picture files and movies (pr0n, stupid kitten videos, etc.) or files for business, it's all the same pipes, no?

If they want to charge more for more bandwidth, that's fine - they can do so and already do. However, folks need to realize that it's rarely your inbound bandwidth that's the problem - it's the site you're accessing's ability to pump out the info, as well as all the servers, routers, and junk in between.