What actually happened seems pretty clear and not so mysterious.
When Mindgeek took over, they deleted all videos they didn't have clear paperwork for. That meant almost every video from before 2015 vanished overnight one night in December 2020, during the pandemic, when most people had other priorities.
This was at the exact same time as other sites, like Pornhub, were having MAJOR drama with the major credit card companies threatening to drop them. That's clearly why Mindgeek did THE GREAT PURGE.
The company gave some BS claims that they were reorganizing, or something, and that the videos would all return. Nobody believed that, and the videos never returned. Mindgeek probably just hoped the BS excuses would placate people until their attention moved to other things.
Only a handful of us remember the greatness that once was Sean Cody:
All their best models have vanished forever, pretty much.