No. Obama won COMPLETELY because they were better organized and got their core vote out, and much of the base was so PO'd at McCain that they would never vote for him. Palin recovered a significant number of those voters, but not enough. There is zero evidence that "undecided and moderate" voters cost McCain the election. The "country club" Republicans (Schwartzenegger and others) have been trying to sell this for the last forty years, and it hasn't worked yet. They had their way completely in this election, with their preferred presidential candidate, and lost their asses.
When Republicans run as conservatives, they win, witness Reagan, Bush I (who lost because he betrayed the conservative position on taxes), Bush II (who ran as a conservative, despite the fact that he governed as a moderate). McCain refused to run as a conservative, and lost his ass.
Well, I can’t prove a negative. No one knows what might have happened if, say, duncan hunter or Fred Thompson would have run. But hold on, they did...and they got voted down.
I think conservatism is not as popular as you fondly think.