It’s ultimately following a general online trend here. YT and other platforms were similar in that regard. From just random people uploading things for the fun of it, to an over-commercialization that turned everything into clickbait and how to make your content be the best for monetization purposes. In regards to porn I think the great Pornhub purge also killed a lot of interest of the few remaining people who did this for fun. Not everyone wants to personally expose themselves via ID for verification purposes.