Of course you can...ANYONE can that was grandfathered in...that wasn't the point of my post, the point was that when AT&T decides to STOP allowing people to have unlimited data plans, as soon as your current contract is over (or if you're not currently under contract), at ANY point they can simply switch you over, as they have ZERO obligation to you to provide you with unlimited data for your iPhone.
It actually reads quite clearly in the contract that after a contract has been fulfilled, AT&T reserves the right to change a customers features based on current data/voice plan offerings without notice...meaning they can change your data plan to the tiered system and send you a message saying "Enjoy your 2/4GB per month!" and there's NOTHING you can do about it outside of switching providers.
That day IS coming. The throttling is a temporary fix for them...it's so clear to see, the companies are all waiting to see which one of them makes the first move, and then it'll all come down like dominos...sounds like conspiracy theory right? Just watch...