Superman soon had lots of company and lots of competition! What do they have in common? All superheroes have some type of extraordinary power or ability. Their "superpower" can be something they're born with: Superman, Wonder Woman, Thor. It can be the result of an accident or mutation: Spider-Man, The Incredible Hulk, Wolverine. Or, it can be simply a skill they have learned, honed and perfected beyond the average: Batman, Hawkeye. They all have a strong moral code and a motivation to rid the world of some menace.
There were some slight changes from Ditko's armor to the one featured here, mostly with the face mask, but since those changes were made, that basic design has been fairly consistent. Now, Iron Man's armor has obviously been altered in other ways as technology has changed, but the basic yellow and gold design has been used almost exclusively since then. No matter how fancy the armor gets otherwise, the yellow and gold set-up is a catchy design.
By the end of the 1940s, superheroes had lost a lot of their appeal to the public. National Comics (now DC Comics) went from having dozens of superhero titles to only having a handful. Most of the members of the Justice Society of America fell out of sight in the world of National. Flash and Green Lantern went from appearing in multiple titles to not appearing in any books at all!