if I'm recalling correctly, Comcast still owns a piece of Hulu with Disney. I imagine Disney is going alone on another streaming service.
This business is so intertwined, but content is still king hence why the IP holders hold all the cards.
Disney will still own Hulu though, they just recently said they put most of the mature shows and movies in Hulu and keeping the family-friendly ones for its own streaming service. With Fox IPs in the mix, it would Disney a good reason for its own streaming service, where people can choose plenty of valuable options to choose from. Without Fox, Disney's streaming service wouldn't be as attractive and can be potentially useless.