While her post did send shockwaves inside Uber and the Silicon Valley at large, I think, it was Mr. Kalanick's incriminating involvement in the Waymo - Uber lawsuit that ultimately sunk Mr. Kalanick. He simply had to go.
But only after Waymo became involved, there were rumors of the board moving to push him out.
It would have been nice if her allegations brought him down, but sadly it doesn't seem that way. In other words until investors saw their money potentially going down the drain in a lawsuit with Google, they kind of looked the other way.