Palin is not next. She does not have the infrastructure that the other guys have and infrasturcture counts a lot.
It is why Obama lost 2 pts in Ohio between 2008 and 2012 while losing 14 points in neighboring Indiana in the same time.
So you have no idea how many blogs there are that support Sarah Palin, how many conservative, Republicans, Reagan Democrats, Tea Party, populists and libertarians will drop whatever they’re doing if she declares, etc.?