It's because he made himself public as shit. John Gotti's reign didn't last any longer(at least on the streets) and he's known as well. It's all about how "media friendly" they are.
Castellano got hit on December 16th, 1985. Gotti was arrested at the Ravenite for the last time on December 11th, 1990. His reign was almost five years to the day. But don't forget, he was also held without bail during his first RICO trial. The guy had maybe three years at the top all total.
