I think that there are several problems with trying to start an all-new superhero.
Firstly, comics aren't selling awfully well, outside a select few.
Secondly, most of the main powers have been covered. Flying, super-strength, ability to fly, elasticity, invisibility, etc etc. What can a new hero do that hasn't been already done?
Thirdly, the most successful comic strips or superheroes of recent years have been deconstructions of the genre. Dredd, Watchmen, Marshall Law etc. The most successful original movie or tv ones such as Heroes, Misfits or Chronicle have eschewed costumes, capes etc. And they were ensembles rather than single-hero movies, so no one character was ever going to become iconic.
So unless someone comes up with a really original and compelling character, I don't think that the status of Batman, Superman or Spider-man is likely to be threatened.