Have you considered that it's not some moral high ground of "being diverse" that is guiding these decisions? Maybe its market forces driving this push?

Star wars is a great example. Maybe the cast they chose makes their movie more palatable for a more diverse, but also MUCH larger audience, and therefore they make more money.

Obviously the old movies were successful but whose to say they wouldn't have made more money if they were more palatable to people of color or women. As it stands, the main demographic that enjoyed the old movies were white men.

Maybe a lot of women didn't appreciate that Leia, as a powerful woman, was also put up as a sex symbol. Why couldn't she be like the warrior, Rey? I know my 6 year old niece loves star wars and dressed up as Rey for Halloween, they've made a lifelong fan.

Maybe black people weren't drawn to the original movies because the token black guy, Lando, was a minor supporting actor who sold out his friends? Maybe more young black boys identify with Finn, and therefore will be turned into lifelong fans, buying merchandise and dragging their parents to the theme park in Florida.