There is absolutely no possible way many parents didn't know what was occurring. A few victims, sure, the parents might not know. However, a cyclical rampant abuse of this size means many children over the years, which means many victims, considering children are only children for a brief time.

So at this scale, many of the parents would have to know. Statistically, it's impossible for them not to. Also, the frequency of victims, many of whom are not famous, would be spilling the beans for publicity and money, as well as justice.

I believe that if this is all true, parents would have to be involved and paid. The parents could easily brainwash the kids and help keep them quiet and most likely convince the victims it was normal or somehow a good thing.

I would look at the financials of many popular 70's-90's movies involving a cast of many children ages 11-16, and see which "extra's" inexplicably got paid much more than others, or kids that had been paid for brief roles and paid an uncanny amount. If that didn't dig anything up, I would want to see if there any of these kids had parents "working" on the film in some capacity and if they had been paid higher than average for their services.

If any of this is true, victims silence and parents pimping their children in Hollywood wouldn't come cheap. I imagine the abuse of someone's kid over 4 years, would cost a few homes worth of cash. I feel disgusted thinking about it, but parents being compliant and gaining something, are the only possible way I could imagine this could occur to young, white American children for 30+ years, some even celebrities, when the victims must be in the thousands by now. Especially since the criminals have money themselves, which paints a pretty good target on someone's back, despite their ability to buy top notch legal council.