Someone estimated that it was only a few days after the movie camera was invented that someone was convinced to perform a sex act for it.
There were "French postcards", "Tijuana Bibles"/"8-pagers", white-label "party records" sold under the counter, "Adults Only" exploitation films, smokers, stag reels, "limited edition book clubs" that mailed their novels in a plain brown wrapper, etc. Prostitution is called "the world's oldest profession". What is different is that it is all out in the open now and young children are confronted with it every day.