Jobs also acknowledged that Apple can't make enough bumpers to satisfy demand, so it will source cases from other vendors as well.

Holding the Nexus One with an Apple approved fingertip grip, not touching the body of the phone, we saw no appreciable drop in signal.

And because the 4 needs different cases than the 3G/3GS, Apple had the iPhone 4 case market all to itself for a few weeks, and mostly to itself for a few months.