Is there a logical reason for the location of the OnStar antenna on the front side of the vehicle vs. the rear center of the cab?

I don't know their logic, but I wish they would have left well enough alone, and kept the dual antennas for XM and OnStar.

Now in 06 they share the left side antenna, which is already problematic with getting broken off in car washes. The older (up to 05) style was a 3" rubber screw on antenna, and had plenty of "give" if it got hit, bumped, whatever. New ones just break off, leaving the electronics exposed to getting ruined by water/snow. I have seen about 10 of these broken off at the dealership by car washes, some already broken when unloaded from the car haulers.