I used to work in the movie industry and (other than at the very bottom quasi-amateur indie film level) most people in the industry understand this stuff really well. There are two daily newspapers that just serve the film and TV industry and 75% of the content is about who is making or breaking deals and what the legal and economic implications are. Don't forget that the industry wen through this cycle many times already, from verticals (studios owning theater chains), to TV, to home video, to DVD, to streaming etc. etc.
Decisions and litigation like this are often not based on the merits at all. They're poker games in which the bets are the amount of litigation expenses people are willing to bear. Dis ney might look at this and think 'Scarlett Johanssen could easily win this case, but she's probably not willing to spend more than $10 million on legal fees over a period longer than 5 years. Maybe it's worth putting in $20 million on legal fees at our end because we stand to gain $1 billion over the same period by having a stronger bargaining position in other negotiations.'
Scarlett Johansson could walk out of any future business with Disney and still be a big star and make money with other studios. She has legions of fans that will keep her a star for as long as she wants to keep acting. But will it hurt Disney to make an enemy of her? Probably not at all. However, caving in a contract dispute makes them look less powerful in all future negotiations.
Contrary to the message their movies convey to the public, within the industry Disney much prefers to be feared rather than loved.