https://www.cracked.com/article_43763_its-been-exactly-40-years-since-frasier-crane-first-showed-up-on-tv.html

And the less said about Frasier's Dr. Pepper commercial, which the character of Frasier Crane would have no doubt loathed, the better. Amazingly, today marks exactly 40 years since Frasier Crane first appeared on TV. On September 27, 1984, Frasier showed up in Cheers' third season premiere.

How did Frasier manage to fill the void left by Diane (https://www.quora.com/How-did-Frasier-manage-to-fill-the-void-left-by-Diane-on-Cheers-and-become-an-essential-part-of-the-show) on Cheers and become an essential part of the show?