It was amusing to look indifferently at some "actor," and then have him tell you his well-known name and why he used to be famous.
Besides Conrad, a losing candidate for vice president appeared in the ad, and more that I can't remember.
So the sentence is referring to an ad campaign of ads showing "famous Americans which nobody recognized any longer."
The idea of the ad was that you need American Express because no one will know who you are when you're traveling, so you'd better have a well-recognized, highly-trusted credit card.
The ads made this point by showing you that if a failure to be recognized could happen to THEM (what with their being so famous and all), then it will for SURE happen to YOU.
Student or Learner