Afaik the exception pornography initially had which made it exist outside of sex work rules hinged on where the money came from. If it was from someone engaging in the act, then it's prostitution. If it's someone else, then it's acting.
But arguably, the payment here is more direct so I honestly think it wouldn't be obvious. The customers are paying for the purpose of potentially live sex work merely with a barrier of technology between them.
I'd imagine it's the same as the peep shows where someone pays to enter a booth to watch a promised tantalizing performance with a transparent barrier between the participants, but I really don't know.
The second interesting thing is about teenagers. The original argument again, relied on two models: one where the person is getting paid by a participant, which is seen as abuse, and the second method where they may or may not be paid but an adult is doing the recording and distribution, which is seen as exploitation.
But what if it's the teenager themselves that turn on the camera and presses record entirely on their own? The exploitation and abuse arguments no longer hold so I'd imagine that this too may not be so obvious.
The argument that it's illegal to consume or possess the material may still hold if the method of production can't be demonstrated but what about to produce and distribute the content?
I certainly would have pursued an amateur career as a teenager for extra money if it was available. Also, if the content was still floating around now, 20 years later, the only thing I'd feel would be extremely flattered.