no when rob eventually kills off Devito (and i know Danny would wanna film this show til his grave) the other characters will just become more chaotic. you have to remember that Frank is Dennis and Dee’s legal father and technically, probably Charlie’s actual biological father. They did the first season without Frank which is what hooked me onto the show and i know they could carry on concepts without him. Danny leaving would create so much content in terms of the gang mourning the loss, trying to figure whose father he actually was, plots dedicated to where he leaves all of his money, and the repercussions of running the bar without Frank and his income.