Walk with me for a bit.
Bruce Wayne + Asian vacation = Batman
Lamont Cranston + Asian vacation = The Shadow
Stephen Strange + Asian vacation = Doctor Strange
Now, I know that a good deal of this is a by-product of the era (apparently, there was a great deal of cultural fascination with the Far East pre-WWII), as well as some wanton plagiarism (in the same way that Doc Savage was the Man of Bronze and Superman was the Man of Steel). I guess uniqueness wasn't valued all that highly when creating pulp heroes.
And I was almost thinking that white heroes were the only ones with such a firmly encoded origin—but when you look at black or native american heroes, they've got the same ticks.
Jefferson Pierce + ghetto = Black Lightning
Luke Cage + ghetto = Power Man
John Proudstar + reservation + Vietnam = Thunderbird
Forge + reservation + Vietnam = er, Forge
There are, apparently, no black heroes not from the Hood and no Native American heroes not born on a reservation. While those locales can be defining elements, they're not exclusive. John Proudstar couldn't have been from Santa Fe? Luke Cage couldn't have been raised in the rural south? He couldn't have been the child of freedom riders? Sure, you get your odd men out like Black Panther, ruler of an African Kingdom, or Storm, goddess of the African plains, or Blade (wait...a vampire hunter from the ghetto), every now and again, but they're the exceptions, not the rules.
And, jeez, try finding an Asian character not adept in the martial arts (I'll give you Jubilee, find another one). Maybe that's not entirely fair. I've been combing through the Marvel Universe and pretty much every character is "an expert in various forms of martial arts."
Maybe the get-rich scheme inside the Marvel world is to open a friggin' dojo. In the hood.