It's not that the margin was so slim, it's that they lost their own wave elections. If the GOP couldn't win with an incumbent with 8% unemployment and a bad economy, then how can they win. If they can't win when everything's in their favor, how can they win?
The choice was this - A Massachusetts liberal, or a Chicago liberal. They were smart enough to know these were their choices, so why bother to vote?
It doesn't matter what a politician says during a campaign. It's what they've SHOWN themselves to be is what matters.
Most people figured it really wouldn't matter. Not one of them was Moses. Not one of them would free the tax slaves. Their livelihood would still be stolen from them and their families. Nothing would have changed.