Other manufacturers can get away with using them because they aren't shipping anything like the sort of volumes that Apple does (i.e. millions of units per month) and/or can slap in a huge battery to compensate for the power drain.
You might be right but I just know critics are going to complain if Apple doesn't release a 4G iPhone for the rest of the world, like they did with the iPad.
Also how come they work in the US/Canada but changing the frequency for the rest of the world would cause battery and production problems?