I remember an article by a black writer who pointed out that all the Black Dramas were about Slavery or the Civil Rights struggle. Imagine if all the White Dramas were only about WWII and the Sixties.
Terry Gilliam strikes me as one of those older white men who were progressive or even forward thinking for their times, but times changed and Terry stayed the same.
As for "dealing with reality" well, unlike Terry, poor people deal with reality every day (and poor people-of-color deal with even more of it) so yeah, we need to escape every now and then. But look at the last two decades: Superheros followed up on trends of Vampires and then Zombies. I think they admit sub-conscious things we're not ready to say out loud. After being preyed on by metaphorical bloodsuckers and reduced to screen zombies, we just want to feel empowered again, which is what superheros do.