Why would Mel`s career even remotely be over? He has been acting, producing, directing and distributing all of his films himself with no outside involvement.
Plus many, many, many people are supporting him through this. The public doesn`t care, nor should they. He has a great talent and why would his personal life matter anyways?
If Mel was a writer, he could continue to write books, articles, etc.
But an actor needs co-workers, other actors involved, directors, producers, agents, publicists, etc.
My guess is he can still make a living off his old movies and fame, but he's not a bankable star anymore.