Perhaps, but Superman's image itself has become an Icon of sorts, even if his in universe character doesnt specifically represent that. (Just a superhero with a heart of gold)
Actually, id argue Superman became more an icon than Cap was. At least, it feels that way.
Of COURSE Superman's image has become an icon. He is an icon. His S is one of the most recognizable symbols in the world. That's because for a lot of people, comic books are modern day myths and legends, much like the Greek Gods of ancient times.
And yes, Superman is more of an icon than Cap. Superman is the most iconic superhero of all time. A close 2nd is Batman.
Oh! Well yeah, I knew that much. There's more to Flash than he runs fast, after all.
There's more to the Green Lantern than... well, a magic ring. I know a bit about that one myself and the myriad of off branching and what have you. There is more to peanut butter than Jiffy. I can think of a buncha different variants and flavors and the interesting history behind peanut butter.
Anyway. I accept that then, I wasn't entirely sure where you were going with that at first, after all.
Oh well. I still think Captain America is a douche. >_>
Also, he has balls too, given I wouldn't be caught dead in his outfit. Anyway, carry on, gaiz. That's my piece, I don't plan to get too involved after all.
Well I can tell you that you're not wrong, so to speak, regarding Flash & GL, as well as most superheroes. In the past, especially with DC, they weren't much more than what you said, being a guy who runs fast & a guy with a magic ring. It's why Marvel was so popular when they came along, because to them the person was more important that the powers, and it changed comics forever.
LoL, and listen I insult Cap ALL the time. I clapped when Tony used his shield to prop his device up in Iron Man 2!
If you or anyone is curious as to my take with what Superman TRULY represents, in my eyes, I'll copy & paste a post I made on another forum regarding the subject.
One last question, what IS the name of the current VA for Zero? I think I missed it. I really like him, seems better than Lucas personally. Don't haet me. 
His name is ADAM, THE BLACK RANGER!
And to be honest, I like him a lot as Zero's VA too!