They have to say that, though. Can you imagine Boehner saying "Sure, if Obama wins, we'll change our attitude, so a lot more would probably get done in the second term?"
Boehner's been trying to make deals for the last two years (once he got the majority) and been kneecapped by the Tea Party Caucus the entire time. Don't imagine that the Republican leadership doesn't know that the reactionary agenda being advanced by their base is toxic -- if they didn't, the nominee would've been Rick Santorum. (Actually, Mitt Romney is a fascinating example of what happens to a seriously divided party -- when your requirements for a candidate are contradictory and implausible, you get a contradictory and implausible candidate.) I will go out on a limb and say we'll see more compromise in Obama's second term. Obstructionism is what they did to get a Republican President in 2012, and look how well that's working out.