No, my guy. Spider-Man, X-Men, the Fantastic Four, and the Hulk were all A-list characters before the MCU. Even people who didn't read comic books or watched cartoons and stuff could recognize those characters before the MCU.They all were B or C list before they had a hit film. Hulk had low budget live action tv shows before taking off in movies. Spiderman had low budget live action tv shows nobody watch before taking off in movies.
Cap had low budget live action movies before big budget movies took him to another level. FF4 had unreleased movies nobody even saw before taking off in big budget films. Iron Man and Thor did the same thing.
They're all A list now because of Sony, Fox, and Disney. it's mostly just the studio they went to that determined which one popped off first.
However, DC is home to most of the iconic superheroes (Superman, Batman, Wonder Woman, The Flash, Green Lantern, Aquaman, etc). It's just that DC (really Warner Bros.) have let Marvel each their lunch in live-action films since the MCU started (for the most part)