It's the end of an era. He's quit and they'll have to find a replacement.
Of course, the show will go on. Eras end. New ones begin. The way they can just change the guy in the role every few years is key to the long-running success of the whole thing.
Shame it's always a white guy. Why not try a woman or a black person next? Just once.
I know some people have a problem with that notion, saying they'd be unable to relate to the character if he changed gender or skin colour... but I think that's just sexism or racism in disguise.
If the role can be played by a completely different guy every few years - with a different height, different accent, etc. - then why can't he also have different naughty bits or epidermal pigmentation? This last guy was much younger than the last one, for instance!
I think it's silly to insist on such arbitrary notions of continuity when all the underlying notions are so fantastical and absurd. Part of the appeal of the thing is that it's pure fantasy! You can do whatever you want!
It's bad to let the hardline fanatics insist on a 'correct' version of how things should work. It stifles creativity. Makes the whole thing boring. Inaccessible. Off-putting. Unappealing to outsiders. It'll cause the crucial 'numbers' to go down.
Still, that's cults for you.