It's not just patriotism, though that's a big part of the bee up Hollywood's bonnet, I'm sure. They've spent so much time building up the "Ugly American" stereotype that they don't want to damage the brand. But more importantly, I think, it's the optimism.
For all the propaganda about "Brightest Days" and "Heroic Ages," thanks mostly to O'Neill in the '70s and Moore and Miller in the '80s, heroes are still only "cool" if they can brood obsessively about their "burden" (of making the world better, mind you) and hiding in the shadows so that nobody can ever figure out who he or she really is.
The message was supposed to be that any loser you meet could be saving the entire universe during his lunchbreak, whereas today they're written more as the kid who's terrified that Coach'll find out he's been taking ballet lessons. Hopefully, the irony isn't lost, here, that this is coming from creators who obsess over how much credit and ownership they get for their own work on characters who are terrified to take any such credit.
Well, I guess you CAN be willing to take ownership as a superhero, but you need to be an adrenaline junkie or in it for the fame and fortune, like the classic Booster Gold (or the original Elongated Man concept, if we want to go back further) or the recent Iron Man movie. In other words, you can put your name on your work only if you're socially deficient somehow. Nobody would ever do it because it's the responsible thing to do. "Real heroes" obviously cower in the shadows behind a fake name (heh--present company excluded, of course!) or only associate with other people "like them."
And yeah, "Smallville" is a big part of that. It's not just the costume, but the very nature of the series that Clark is...kind of a jerk, more interested in his own life than improving the world, and absurdly insecure on top of it all. And yet, somehow, everybody bows to him as the greatest person ever to walk the Earth because of some "destiny." Of course a character like that wouldn't wear a bright costume. The first time someone looked at his crotch, he'd soil himself with worry.
