That’s pretty much it. Mostly through the media, but in small part on her own, she was turned into a caricature of herself. When people think Sarah Palin, whether we like it or not, people think Tina Fey. Her chances of running have been zero since the last election.
While he did give her the opportunity I mostly blame McCain for not giving her enough time to study up and prepare to be the Veep nominee prior to being cast to the wolves.