I don’t believe that the reason the recent Disney owned films have underperformed is anything due to diversity of casting and have more to do with the general economic climate, poor marketing and fatigue.
I have primary aged kids and Disney +, never heard of Strange Worlds until this thread- suggesting it may have had problems reaching its core market.
The trailer for Lightyear looked boring and derivative, which is why I didn’t bother watching it, and neither of my children like Toy Story. Although in Lightyear’s case the same sex kiss may have affected its performance because of foreign markets who will not show same sex relationships on screen. I assume Disney knew that when they were making the film though, and chose to include the scene anyway.
And is the Little Mermaid underperforming? I heard it was doing very well.
As for Marvel, I think that’s more to do with fatigue with superheroes. They’ve dominated cinema for over a decade, cost an fortune, and a lot of people who enjoyed those films previously have had enough. People are less willing to do a load of homework by watching several other films and a Disney Plus series to understand the plot of the latest release. The diversity of the cast and new heroes has come at a time when people are just fed up of cape films in general and looking for something new. Additionally, the quality of the Marvel TV shows have been patchy and/ or sometimes niche in appeal.
I think Disney have made bad business decisions, but diversity isn’t one of them.