So yes, that is happening at a non-negligible scale. In fact it is happening at a scale that is incredible (to me, at least).
The figures I'd want are not consumers or producers but numbers of children. A child being abused 1000 times is obviously awful but its not as bad as 1000 being abused once.
Obvious to you. The problem with this sort of reasoning is that children are not mathematical objects. It is also the sort of reasoning that ultimately leads to the rest of society deciding that us tech people are incapable of setting things up in such a way that abuse potential is minimized. Then you get reactive stuff like this article.
Maybe I've gone the wrong direction, but I'm almost convinced now that it may actually be worse to make public statements linking encryption to child abuse because it potentially paints backdoors as a solution in the minds of the non-technical folks, and potentially makes child abuse closer to appearing to be a "solved problem" and distracts further from progress towards a real solution.
I'm aware now (thanks to you and some others who have horrid coalface experience) that the digital realm is indeed more of a problem than I'd considered. I can't bring myself to accept, however, that mandated encryption backdoors are worth the attention they're being given by law enforcement for the purposes they're trying to align it with.
Is this actually taking place at a non-negligible scale?