This guy is running twitter like it's his personal website. Which, it is. But people prefer services offered by businesses instead of individuals, because businesses have stable incentive structures and fiduciary responsibilities. No one likes it when the rules change arbitrarily every week, so businesses don't do that.
This level of chaos just isn't sustainable. I would never have thought that twitter could lose a significant portion of its user base in a short period. But that could very well happen now, and it's crazy.