It is equal. You think there are only predominant white fictional characters in the world? - very narrow minded view. There are heroic characters from all parts of the globe, from different cultures. Plenty to go around. And if you still dont think that; make some new ethnic characters. Start at the bottom where Superman started and earn your stripes to achieve Supermans global appeal. Dont just hand a already successful white character thats spent years portrayed as white and give it to a black/ethnic actor, thats patronising.
''We dont have faith in pushing our classic or original black heroes, so we'll just race swap an already successful white hero with a tokenized black one''
Thats what it comes down to at the end of the day and it doesnt sound good. Casting James Bond, Superman, Ariel and Johnny Storm as black is basically the studio admitting they cannot be bothered or they have no faith in promoting their classically black characters or taking the risk to produce an original black character. Thats real racism.
There is a limited amount of validity in terms of stating that there are characters that are PoC that should probably be given "the push" these days if indeed commintment to diversity in media portrayals is in any way sincere...
But the rest of your argument is quite, quite silly.
Things change. Period. And looking at even classical mythologies they changed as well as circumstances in the cultures that embraces the ancient stories changed, or the stories became tailored to the peoples that adopted them. This is why even the stories of the Egyptian, Greek and the folks tales and myths of Western Europe often have multiple versions of the same set of mythological characters. Over THOUSANDS of years things changed, adapted, some things ommited others brought in from other sources and integrated into something to serve where the culture telling this story to themselves were at that point.
The pop culture that we debate, analyze, celebrate and deconstruct literally every day here on the hype is merely decades old. This is hard to come to terms with but the truth is that the Superman or Spider-Man that you or I hold as some kind of Platonic ideal as they are thought of NOW will not be exactly as they are now as they cross over into another century of existence, if they are LUCKY enough to survive. And one of the inevitable ways they and what those stories stand for and what value people can get out of them will be changes that the people that originally expereinced them would find strange or unimaginable. But without that... These myths will die.
Cinderella finds it's actual origin likely in a tale going back to Ancient Egypt and recounted by the Greeks, and there are Asian variants that made their way West from China. If you grew up with the Disney animated film and it's wide reaching iconography you would think that for all time it had been a tale from Western Europe.
Look... The facts are that there is still a dearth of big budget Hollywood productions with lead roles for non-Whites. And despite all the drama that occurs when this happens, I'm sorry, the outrage it causes seems to be one that acts as though some harm is being done, real material harm, to people that are against these changes. In a country centered around ascent to a common set of laws and not about the primacy of bloodlines or ethnic background (It's always strange to hear the wailing about "hyphen-Americans" since... Well... The terms "American" is in there. It's obvious that in spite of obviously self designating as part of a sub-group within a wider populace that an incontrovertable connection to wider group is inherent in the term...) is it really a wonder that fiction, especially FANTASY fiction is going to find ways to adapt itself to a changing demographic? Is it surprising that the corporate overlords will, ya'know... take a measure of the marketplace and sell their wares (i.e. the characters and concepts they have a copyright to) in a marketplace where the demography is shifting?
Now... Of COURSE there are going to probably, even likely be tons of exemptions from this. Lots of various characters or concepts or stories that probably don't or can't lend themselves to these kind of changes. And yes, sorry, but given the history there is a difference in taking the few well known and well established PoC characters that might garner the budgets and high profile support of Entertainment Conglomerates and changing them to being Caucasian/White and race bending the likes of Bond or Bruce Wayne. These are after all, questions of art and culture. This isn't a math equation. Nor is it a zero sum game where if there is produced a race bent version of some character or story that for all time something has been taken from White people for all time or some such.