Who Really Writes Those Books "by" Public Figures?

As I have remarked here before, people seem to be less sophisticated these days in regard to the matter of the actual authorship of books by public figures than they were in the past. Certainly there is less casual acknowledgment of the reality that such figures did not really write the books with their names on the bylines (and often, their faces on the covers), one memorable example of which is to be found in John Kenneth Galbraith's memoir A Journey Through Economic Time. There he observed that "[t]hose who publish books on their experience in public life have often a rather delicate task to perform" in their "offer[ing] their thanks in a suitably subtle way to the individual who actually wrote the book, while somehow minimizing this considerable delegation." I imagine his once rather broad audience (The New Industrial State actually was a #1 New York Times hardcover bestseller that lasted 22 weeks on the list back in 1967) chuckled along with the quip, but I suspect that today far fewer can follow his prose well enough to notice the joke, let alone get it.