The emperor has no clothes. Whether it's just his natural personality, or serious internet-poisoning, or some kind of substance problem, Musk has a habit of making rash decisions, and buying Twitter for way more than it was worth was one of those.

So he's scrambling. Trying to find any way to make it pencil out, using all the stunts he can think of. "X" is just another one he'd kept in his back pocket for decades. He'd obviously always liked the brand, since "X.com" was part of his PayPal story, and he named his space company "SpaceX", and one of his Tesla models, and his kid.