Does the (deeply tedious) myth of the cowboy really have that much of a death grip on the national consciousness? Back in the fifties and sixties TV and the movies were crammed full of horse operas -- no more. HBO's new expletive-intensive Western (which I haven't seen) is the first major Western in years, and it doesn't seem to have attracted much attention.
I think (hope) that cultural archetypes burn out after awhile. If they didn't, Scandinavians would still dream about launching Viking raids instead of being preoccupied with keeping the welfare state alive.
Carl