Wrong.
Sorry, but Palin did NOTHING to help the GOP win this. I disliked Romney intensely but I voted for him, even though I was a Newt fan and Romney and the Romney-supporting Rush Limbaugh destroyed Gingrich. But Palin could have had an impact on the primaries if she had come out early and supported a candidate, since she was not one herself (which she decided so late it kept people like you on the fence).
As I say, there may have been personal reasons, but that’s just tough. As a politician or even a political strategist, Palin is simply not there.