Whether KS can or cannot survive without PD, it was her decision to leave, permanently or temporarily. The production house can either replace Bani or think of another solution. They won't know until they try, its not as if PD did not know the situation would come to this when she signed the movie. Its true, KS cannot survive without Bani but the same with Jai. Either of them leave, the soul of the serial goes. But if such a situation does arise, what would anyone do if they were in the shoes of the producer? Winding up may not be the solution as there may be contractual agreements.
A lot of times, its easy to sit on this side of the fence and give our comments. But maybe one has to put oneself in the shoes of the other side! Of course, I'm not defending the destructives 😆 but, maybe they too are only trying to salvage as best as they can or know how to!!