To be fair, Google and Facebook both do plenty of content scanning, but you’re right that it likely doesn’t use the CSAM pipelines. Apple’s pipeline is probably even harder to repurpose since it’s designed very closely for this use case.
Unknown re private scanning, however Australia and UK have rigorous internet censorship regimes that block copyright infringement and gambling that use exactly the same censorship infrastructure that was build to block CSAM in the early 00s.
