Another By Author Of 'Scarlet Pimpernel'

I noticed in the IMDB writing credits that the original book is by the Baroness Orczy, author of one of my favorites, "The Scarlet Pimpernel."

This fact is not even referred to by any of the reviewers. Why not?

Nobody compares this movie to the great Leslie Howard/Merle Oberon vehicle. Why not?

People refer to the plot of "Emperor's Candlesticks" as silly. I would hardly call the plot of "Scarlet Pimpernel" silly. Has the Baroness's work been so subsumed by Harold Goldman that little of it remains?