It wasn't Marvel's fault that we didn't get Miles. Sony literally put in their contract with Marvel that they only wanted a white actor playing Spider-Man for some stupid reason. So if anyone is to blame for not having Miles it's Sony.
I literally watched Marvel execs say “we don’t even need to change Spiderman from Peter Parker” like unless you were literally in the same room as Sony and Marvel when they stipulated and signed that contract, I’m still gonna stick to side eyeing Marvel. Because even if it was in their heart to have Miles or care about diversity, their response would have been “we would love to explore the possibility” or something along that line. Nope, they literally said “it should only be Peter Parker”. Even Stan Lee said there’s no reason for them to change Spiderman from Peter in response to criticism from fans about Spiderman Homecoming. Like who are you trying to fool? “Contract” (again, please show me proof of this) or not, Marvel would not have chosen any other actor than a white actor, more specifically, would not have chosen Miles Morales over Peter Parker. Look at their history of casting. They ain’t that brave or evolved.