Every professional contract I've ever seen contemplates expansion into future media and markets; it's a technology driven business that has to follow customers to where they are going, and industry lawyers are fully aware that if studios or production companies had the option, most of them would happily relocate to the Moon or Mars to avoid paying out, while maintaining an office on earth to litigate their own copyright interests.
When I was in law school at UCLA, I considered going into entertainment law. I attended a presentation by a famous entertainment lawyer who said that the lawyers in show business are not actually the most talented — unlike other industries, the big players don't hire primarily from Harvard, Yale, etc.
Instead, the halls of Sony Pictures or Fox are lined with graduates from second- and third-tier law schools who had a foot in the door because of a family connection.
The reason he gave for this is that entertainment law is not as complex as other areas of law, so the basic contract work can be done by a not-stellar lawyer. This was a 15 years ago, and perhaps times have changed. But I'm sure that family/industry connections are still an important part of getting these jobs.
But I do think entertainment lawyers are still very good at what they do. If you look at a popular reference like Mark Litwak's Dealmaking in the Film and Television Industry there's a heavy emphasis on taking the longest possible view because big openings and box office receipts are only tiny part of the overall revenue stream, and the real money is in syndication, foreign sales, merchandise etc. etc.
edit: I heared the above several times over the years, but it appears it may not be true:
https://www.businessinsider.com/sylvester-stallone-on-never-...
IIRC, it was merchandising rights. Sales of the Star Wars action figures were huge, and my understanding kind of unprecedented.
Apparently Warner dealt with this unexpected issue differently:
> WarnerMedia chose to renegotiate many of its talent contracts that, like Ms. Johansson’s deal with Marvel, were tied to box-office performance. Warner Bros. paid more than $200 million to talent as part of the amended agreements.
But it's at least possible that they did not anticipate that Disney might release a film in one of their tentpole franchises at the same time as in theaters. Or, more likely, the tried to get Disney to commit to a specific box office exclusivity window and Disney refused and/or offered something different in exchange which, in the absence of a pandemic, looked better by comparison.
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.
Also the box office in general has been destroyed recently because of the pandemic. What would have likely been $+150M opening weekends and close to $1B totals revenue (or even more) are reduced to fractions of that.
EDIT: Even worse, it was actually to be released in May 2020, thus the negotiations for salary were likely done in 2017/2018 or possibly earlier. Disney+ wasn't even announced back then.