The answer to “Why” is because she is in politics for the fun of it.
She has adoring fans who pay to hear and read how she has never done anything useful in her sorry life.
My take is that it's for the power. Megalomaniacs crave that power over other people. At her age and her net worth, she could retire quietly. Her mental illness compels her forward. She must control the stage, the script, all the players thereon, and all the people who finance the play (especially them). There is no torch to pass on. It must burn in her grubby, grimey hands forever.