Discuss @Charles EP M. s latest article here
I really don't know enough to be able to tell if three companies can survive where only two did historically.
I do feel obliged to point out that the character Black Knight was revived OTL as part of the Avengers
Yeah, I cut that bit for time - Roy Thomas was a fan of the old Black Knight IIRC.
You're right that someone will eventually do superpowers-as-minorities later but, of course, who? And "when", at that, because if it comes out in the late 60s or the 70s, it's coming out when black activists are more radical, Stonewall's happened, feminism's in the second wave etc and your hated-and-feared superheroes will have a different response. (Maybe this is the equivalent of Green Lantern/Green Arrow that Neal Adams is on!)