Still not getting ya I'm afraid... if anything isn't AT&T the only GSM carrier with any real 3G in the USA? Assuming people manage to unlock the iPhone, EDGE would work just as well on T-Mobile (and whatever other smaller GSM carriers there might be). If Apple included 3G, it's not like anyone overseas would be able to use it anyway due to conflicting 3G frequencies used, and here it would pretty much just work on AT&T (until T-Mobile rolls out 3G, I don't know if they've already started), so don't see how it would be a bad thing for them at this time.if the iPhone is only compatable with EDGE in the USA, ATT could have better assurance over who used the phone and on what network. I'm not claiming this is a bulletproof argument, but that could be the reason Apple only included EDGE; to satisfy ATT.
Though, I buy the argument that Apple didn't include it due to technical limitations (size, battery, whatever) but that we'll definitely see a second revision before too long that has 3G for the US market.