From a common sense perspective, the illicit antiquities trade sure doesn’t seem to be anywhere near that of drugs or weapons.
It seems impossible to ignore, however—given the prominence of the topic of human trafficking—the idea that the art industry has been linked with human trafficking.
That is to say, art museums and art dealers are known to be historically involved in human trafficking, including the nightmare of child sex trafficking.
I’d be surprised if streaming media isn’t bigger than the underground antiquities trade, and by a factor of ten or more.