I was being a smart ass, but I agree with your analysis.
I don’t think she would accept, nor would it be offered, but the potential impact would be similar to 2008, and being “older and wiser” she would only accept if she had a completely free hand to do it her way (which is why I says Mitt would never make the offer). But if he were in deep trouble and losing the conservative base, what better VP candidate to secure it?
Palin might accept if she’d got her aim set on 2016 or 2020, as she’d still be young (mid 50s) enough and having served as VP would be a means to prove herself (although there aren’t many examples of VP stepping into the big chair). So “maybe” isn’t such a bad answer I guess.
Bush I, Gerald Ford, LBJ, Nixon, Truman are five ex-VPs that became President and I could go on.
Being VP is a very good stepping stone to become President, it's not a lock but it's a big help.