Because no sane person would pass up the opportunity to be the first woman President of the United States.
Tell that to Susana Martinez and Condoleezza Rice. Or Elizabeth Warren for that matter. Those the could easily be to tier the day they jumped in and all have emphatically said they have no interest.
I'm playing devil's advocate. Hillary is certainly keeping the door open, and making the moves to have a successful campaign if she does run, but I believe her when she says she hasn't made up her mind.
