Aster and Garland will never direct for the DC/Marvel/Star Wars universes.
They both have too strong of a voice and their own way of production. Not trying to say they're too talented, even though both have made one or two of my favorite movies of the past decade... Ari is too in his own space to forfeit to a higher production company and Alex wouldn't let them take Annihilation from him to **** with the ending, therefor succumbing to the terrible early year film release (he knew his film will grow at home/streaming).
Flanagan could maybe do something someday, but not now. He's happy with his King adaptions, (planing to do a couple more) as well as stick to more honest-true horror and not horror construed through a "Marvel character" and such.