True ... but as Professor Higgins points out in My Fair Lady, the Americans haven't spoken English for years ...
There is a rising tide of American name fashions all round the English-speaking world, of course, largely driven by the Internet and reality and celeb TV; but when Steven and Barbra and such began, this was not really the case. And it seems likely that there would be some names that cross the North Atlantic more comfortably than others - notoriously, Randy, but also the sad ones that seem to be made of all the refrigerator magnets left over after the real words have all been made. This doesn't get mentioned much, even in the Comments slot, though it would be interesting.