I agree, I have seen very little erosion to her base. What concerns me, however, is that I have seen no improvement in her standings with people outside of her base, despite having been on the campaign trail for almost three years. (Yes, she has been campaigning, with her reality show, her bus tour, her Fox commentator position.) The question is not whether the hard-core Palin supporters will vote for her - it is whether anyone else will. That is an open question, and it does not look good for her at this time.
If she were to win then the question will remain if or not people will vote to defeat Obama or not. As many have attested to. But I will vote according to who lines up with what I want to see happen. It's time and likely the last time to vote conservative.