I think there's more than one reason for this. One is that our elite US runners grew up in the same culture as the rest of us, so they've "learned" the same things about shoes as most everyone else has.
I also think that if they do have some "natural abiltity," i.e. better physical structure, they may be able to get away with running in inferior/damaging shoes, at least for a while. For me, the matter of running in minimalist shoes isn't a matter of being able to get away with it, it's a matter of necessity. If I wear a conventional trainer I feel lots of little aches and pains much of the time that I don't feel in a minimalist shoe. On the rare occasions that I've run in a really high tech shoe it's been awful, pains, aches, legs with no life, etc. I think that if I were more "talented" I might be able to overcome the handicaps of a conventional trainer and maybe better runners can do that.
As to seeing them in photographs, I expect that they might be persuaded by the company with whom they have a contract to be photoed in models the company wants to sell. Someone who's had a contract may be able to speak more knowledgeably here.
And finally, as others have pointed out, non-US elites often do train in flats or really light shoes. Jack Foster ran in the old Tiger Marthon for most of his life and tells me he still does for the running he does now. I've also seen a photo of him running in the Ultimate 81. Anne Audain always trained in her racers. Gordon Pirie was always in light shoes. Virtually every serious Japanese runner trains in racers or extremely light trainers.