According to wired, [0] Disney paid Lucas Arts $4.5B, which half was cash.
In 2016, [1] The Force Awakens made $1.54B globally. Maybe it's more now.
Lets say that the last Jedi manages the same success? Well, they made their money back and the new rumored trilogy. That's profit.
When you can put Spiderman and the X-men in the same universe as the Avengers and do the next 20 or 30 super hero movies where one, two, three, four, etc characters from the universe makes an appearance?
I'm pretty sure fans of whatever franchise will line up to throw money in seeing the movies.
This really sounds like a no brainer to me.
[0]: https://www.wired.com/2015/12/disney-star-wars-return-on-inv...
[1]: https://www.hollywoodreporter.com/news/box-office-star-wars-...
https://www.hollywoodreporter.com/news/tangled-rights-could-...
Movies continue to make money for years after they are released.
I think it makes sense for them.