I didn't say that I had a magical solution other than hiring the best talent and giving them more freedom to create. Meaning you cannot simply dictate that you will draw me an x version of spiderman and they have to be of this skin color or ethnic group. That isn't diversity is my point. Diversity is diversity in artists, creators, ideas, stories, concepts and characters. And you could absolutely have all of this if they actually put in the effort. It isn't that hard. Indie comics do it. Web comics do it so Marvel and DC could do it if they wanted. But they would rather be lazy and just slap brown or tan paint on an existing character and call it a day.
And to your other point, it isn't a 'problem' that they have these old characters, it is that they want to make money off those old characters and those old white men but at the same time swap them with new variants that are diverse. The two aren't the same and aren't going to have the same impact. But as mentioned, a lot of these changes are done for the purpose of not having to pay royalties to the old artists. So doing a slightly different version of the X-Men with different origins and powers means they don't have to pay the Chris Claremont, Jim Lee, the Stan Lee estate and others any royalties. They are not doing this just for altruistic reasons.
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No you are changing the point. These characters aren't popular enough to be expected to be as profitable in the MCU as the originals. And there is no reason to do it. The MCU hasn't been around for over 60 years like the comics and some of these characters. The OG Avengers haven't been in the MCU for more than 15 years. There is a lot of classic stories with these characters that haven't been done with them. Arguing for the sake of arguing doesn't make these characters as popular as the originals is all I am saying. They weren't as popular in the comics and they likely wont be as popular in film. And yes they have been experimenting with variants of characters, and that happened in the 80s and 90s with all the different versions of Mar' vell aka Captain Marvel, aka Ms Marvel. But each time they actually replaced the old one with the new one as a new person literally took on the title in universe. So it wasn't a swap where they took a character who was one way in the comic and just changed their appearance and background for a movie. That is a totally different thing. Also the multiverse was not used in Marvel the same as DC where they constantly tried to reboot the entire universe. In Marvel the multiverse versions of characters were always secondary and unimportant always basically becoming canon fodder and being killed off in any epic cosmic events. Miles Morales and Spider Gwen being the exception in this case and overall the only examples where this has worked so any reasonable degree. And that epic event called Secret Wars didn't happen until relatively recently in 2015. Before that the multiverse was just there and various teams had stories in it but it wasn't a big part of the comics in general. And the only reason they did that story is to reboot the comic universe in Marvel because now they seem to be running out of ideas an it hasn't worked even though the event itself was somewhat popular.