I'm actually surprised there's this much debate on incomplete/fumble. It seems to me that the receiver doesn't survive contact with the ground which is a well established NCAA philosophy, is it not?
Yes, but that's (arguably) not the case. In this case, the receiver, in the opinion of many folks, was not going to the ground before he was contacted, and had demonstrated a firm hold on, and control of, the ball before he was contacted. Thus, the catch had been completed before the contact. So, if you concur with those claims as fact, then the loss of possession after the contact and before he hit the gound is a fumble. The on-field crew ruled incomplete pass. Replay could have 'adjusted' the ruling, due to the immediate recovery by B. They didn't, which means either they a) concurred with the ruling of incomplete (probable), or b) they didn't think the recovery was 'immediate' (possible, but unlikely), or c) they didn't review it (highly unlikely).