Good points. I think Black Widow is a great example of how, in the beginning, Disney never considered giving that character a solo film. I think that's pretty obvious. She was always meant to be a supporting character, checking off the kickass, bad girl trope box. Like, here you feminist, here's one of your own. Take that and like it. The thing with Black Widow, even though she's had solo comics, it was the films that made her mainstream. As a result, her character blew the hell up. IMO, the BW movie is total fan service for a beloved character Disney did not expect would have the kind of base that grew around the character and actress playing her.
My point is that Disney "gets it" now. Ten years ago, no movie with a female lead was even a thought, much less one with an African hero. I doubt there will be a Storm trilogy. I do think, however, Storm could be deliberately built up to have her own movie. There is more than enough source material for Storm to have her own movie out of the gate, although Disney would likely test the waters with the character first before giving her a solo.
And, check it, the actress who played Monica Rambeau's mother in Captain Marvel, is now the new Bond. I love that so much. I keep saying that could've been Disney breaking the mold with the first African American female hero with Monica Rambeau as Captain Marvel. She carried that moniker before Danvers.