The polls were not off. That is why every poll averager was on the button. 538, Princeton, RCP, TPM all had an Obama easy victory, guess what happened?
Obama didn’t have an “easy victory”.
If you want to look at the electoral college count, then it does look kind of lopsided, but, when it comes to state-by-state voter totals, there were plenty of them that had close enough votes where one could say that, it was very close.
Some of those states were close enough to the point that, voter fraud could make a huge difference. No pollster can account for voter fraud, or for illegal votes, or for voters coming back from the dead to cast their votes, or votes being lost on the way to the counters.