Utter nonsense. That's like saying that all crack pipes should come with free crack.
Apple makes the pipe. AT&T sells the crack.
I use this analogy because if you really believe what you said above, you are clearly quite familiar with crack.
AT&T provides the bandwidth and support for data. How they slice and dice the charges is their prerogative. Whether you're willing to pay for it is yours.
I just have to say that you provided a very god analogy. So good, that I actually spent the time to log in and quote you on this. Thank You for making my night.
On Topic:
I think tethering should be a very small fee, maybe an additional $5-$10. I think $45/month (Tethering + 2gb limit) is way too much in addition to the normal bill.
Actually, by setting a low cost of tethering, maybe many people who use less than 200 mb will in fact start to go over that limit and take the jump to the next cap, which in turn, means more money for AT&T.
On the flip side, if the real reason is because of their network overload, then this seems like a shady way of punishing their customers instead of just making their equipment 'better.'