Could that happen to Disney? Sure. Is it going to happen in the next couple of years because of ESPN? Not a chance.
Yes, ESPN is sinking. But it is not ready to go bankrupt yet, and there are many options that Disney has to either turn it around, sell it, spin it off, or shut it down. Also, for as much attention as ESPN gets, ESPN is not Disney. Disney is a much, much, much larger and more diverse organization than that and virtually every other business unit of Disney has been very successful in recent years.