To me the answer is that NFL executives just aren't very smart.
It's funny because there's so much money at stake, but most of these guys when you actually listen to them speak, seem like freaking morons. The shift in thinking that transformed baseball hasn't happened in football, much to the benefit of the patriots.
I don't know Carr, so not saying for sure, but you sort of see it here. Terrific production, but you've got people saying things like "I don't see the separation" or "yeah, he doesn't have the physical tools." OK, well the Pats will just take him and win Super Bowls with him, thanks.