Batman was also an uphill battle to get made. Don't forget Ulan was shopping that thing around for 10 years and getting the door slammed in his face. There is a perception that comic books are for children and not bankable to a mass audience.
But there were comic book movies in the '90s that people don't recall. Since many filmmakers were still boomers with nostalgia for their parents' generation and Golden Age comics, there was The Rocketeer, The Shadow, The Phantom, Dick Tracy and more. Most of these sucked, but it's because they treated them as either shallow (because that's what they were in the 1940s) or they were made by hack filmmakers on the cheap that did not see the potential of making something better than disposable.
I think Donner, Burton, Singer, and Raimi deserve a lot of credit for proving that they can be viable, creative, and appealing to adults. They also treated the material like moviemaking, which is something I actually feel we're stepping away from now.
Nolan then elevated to an artistic status, which supposedly we're still living in. But I do not see many trying and even fewer at succeeding at matching that benchmark anytime soon.