I would suggest all those years in high school and college where she got a ‘free-ride’...reached a level where she finally had to produce a real study, and she couldn’t do it. As for the college now admitting her limits or their mistake? No...to fire her means a lawsuit and tens of millions to be paid for firing. She has a 30-year job in her hands and will never leave.
They can get rid of her anytime they want. If Harvard continues to lose mega donations they will can her. Even if they have to pay her 10s of millions to go away, that is cheap.