Everything plays a role. Dallas lost because of special teams, but the refs made sure they couldn't overcome that.
Look at it this way. If a game is hard fought and closely played all the way to the end, what difference does it make how they got there? The fact is the game is going down to the wire. Now if a ref makes a phantom call, that could be a difference maker. Yet another obstacle to overcome along with your opponent.
I've never been one to whine about non calls. I wasn't part of the hordes that threw a fit on the non call in last year's championship game. Non calls don't bother me. Calls that don't exist or borderline (either way) calls bother me. Those shouldn't be called and the latter is called constantly.