I guess there was a huge legal fight that he eventually won through argument and opponent apathy, so as long as he doesn’t let the character sit completely idle, he keeps the rights despite no longer giving a fuck either. It’s utterly petty, and if I cared more about Dick Tracy I’d probably find it infuriating rather than hilarious.
It’s beyond suspicion now. In 2015, Carly Simon said the second verse is about him. But to your point of his vanity:
I hadn’t read that before. That’s great, I love it!