Surely this is no surprise to anyone. Although a nice dream, the provision of unrestricted, unlimited, high-speed, tethered internet via 3G is still a long way off (if ever).
It depends on where you live. I find it disturbing that Apple listens very carefully to AT&T and implement the restrictions that they ask for for all operators, while many operators may not have such a problem with data-intensive mobile apps (as an example) that AT&T has. One of my two current mobile operators has two data plans; one 1 GB transfer limit and one unlimited that is really unlimited (no "fair use" clauses in the fine print) and the speed is currently at 7.2 Mbps to be increased to 14.4 Mbps by the end of the year.
They also actively flog 3G USB modem dongles as a competitive alternative to ADSL broadband. They have a music store and download service that operates on 3G and even a music streaming service on 3G.
I'm sure their network would cope with the occasional use of a tethered iPhone.