If Superman (Clark Kent, Batman (Bruce Wayne and Wonder Woman (Diana Prince, were locked into the 30's -40's setting, like many of the pulp and Golden age era characters of the time, DC comics would be mostly defunct.
And while the Silver age reinvention of many heroes and concepts, helped revive the industry, having a still young Superman, Batman and Wonder Woman, right alongside them was key, it is what helped sell it, and was a huge part of it.
The sliding timeline of comics characters, is what has driven it and makes it work.
Those who cluelessly call for "real time" and a universe filled with legacy replacement characters (cause
they grew up with some 3rd or 4th Robin or some other derivative crap who they want to see grow up and replace/be the new Batman) LOL! Would doom and crash the industry, following their model.
They can't indicate a single fictitious character or franchise locked to it's time frame, and replaced by legacy characters, who has had the long staying power and cache: comics, games, movies, merchandise, etc. of the constantly sliding timeline Superman, Batman, Wonder Woman characters.
Star Wars Rey hasn't been around long enough yet.
And most of Marvel's successful movies have used their own classic comic versions(also on a sliding time-scale) , not later legacy version.
LOL to those frantically looking up vintage public domain characters moderately successful today, Tarzan, Zorro, Robin Hood, Peter Pan Dracula, even Sherlock Holmes.
Superman, Batman beat them easy.
A comparable successful character and franchise, which keeps going, with the original character (not legacy), might be James Bond, but guess what movies are on a Sliding-Time scale, same character just constantly modernized for modern audience, like Batman and Superman.
I'll wait...