Possibly. But I am also pretty sure that Superman was never as big as Charlie Chaplin, as Bogart and Bette Davis or Babe Ruth in the 30s or 40s, and that he did not mean then what he came to mean later. Superman truly became Superman in the 50s and early '60s. I am talking Superboy, Legion of Superheroes, Floating City of Kandor, Supergirl, Krypto the Superdog, Luthor stealing those cakes.
You are mistaken. Seduction of the Innocent and the Comics Code Authority killed off EC Comics and the non-superhero adults-only comics, removing them from the mainstream permanently. Superhero comics on the other hand were unaffected. Except for Batman and Robin getting girlfriends to prove they're straight (which was an accusation that Wertham made), it didn't have any effect.After Seduction of the Innocent came out, a lot of superheroes disappeared from comics because of the increased scrutiny of the genre.
In fact Wertham's homophobic screed and the CCA ultimately helped solidify the perception of superhero=comics which persists to this day. It created a perception that comics should be for kids and that the most childlike genres, the superhero genre survived the effects mostly unscathed. That led, in time, to the rise of the monopoly of the Big Two. By the way, the so-called Silver Age, i.e. Barry Allen's Flash by Carmine Infantino, that cover where Flash bursts out of a roll of film...that all comes after Wertham and CCA. The so-called Silver Age lasted little less than 20 years.
He has the power to take over the world and/or end it. He has the resources to do doomsday schemes and has a vague ideology (cleansing the earth) that makes him keen to do it. His scheme Tower of Babel established him as a League-level threat. Ra's Al Ghul is very much Dr. Doom's level...and probably was inspired in part by Doom (what the Green suit with Golden clasps that Adams' intro of him had him wear). And besides, Ra's Al Ghul stories as a rule take Batman out of Gotham and around the world, whereas the Hand stuff still mostly centers on stuff in Hell's Kitchen in Miller's run and afterwards.But, uh, is Ra's all of a sudden in the leagues of Thanos or Darkseid or Galactus?
As someone who studies history and historical process, it's very dangerous to assume that things are inevitable and things always would have been what they are. Contingency and chance are huge huge factors, and that's for the real big lasting stuff leave alone something ephemeral like comics with monthly ongoing titles. The idea that Spider-Man occupied a natural third place after Superman and Batman seems suggestive and natural now, but it didn't necessarily mean that way when it came out. It discounts the fact that Superman himself took a while to become what he became, as did Batman.I very much doubt that.
Spider-Man probably owes his status to the fact that he didn't have solid competition and challenges the way Superman did with Captain Marvel in his very early years. He was also at the outset the most traditional character in a fairly untraditional roster of heroes. The Hulk preceded Spider-Man as a solo title but an ongoing around a meek scientist who turns into a rage monster hounded by the military was pretty hard to do at the time. The Fantastic Four were a family of superheroes led by a 50s Dad and a 50s Housewife, with the cool characters being Ben Grimm and Johnny Storm...neither of whom had secret identities and as such any private life. Daredevil which came a little later had Matt Murdoch who was blind and also some kind of circus dude at the outset.