This nailed it. Public companies have to "grow" and if growth is bot-driven then combating it is not goin to happen. By taking the company private Elon could (in theory) throw out MAU metrics, engagement metrics, etc.

He could "Make Twitter Great Again" by killing the bots, and rage-engagement, and making Twitter interesting and fun again. If that raises Twitters value by 10% he gets a $4.5B return.