Imagine being a musician and Apple deletes your originals to stream your own music back to you in low quality.
Apple screwed up big time in the functionality and messaging around it and some people found their original files deleted when they weren’t expecting it. Big problem.
But it was hardly some plot to scan users’ hard drives for copyrighted content and delete it. On the contrary, iTunes Match would happily launder a whole library full of pirated low-quality MP3s into legal, high quality, DRM-free AAC files.
Even open source products like ClamAV rely on a opaque database of virus strings.
> Why haven't those vendors been already co-opted by governments (Kaspersky on the Russian side, Microsoft in the USA side) into scanning for illegal, copyrighted or secret material and reporting on it
My reply about the only-recent prevalence of E2EE and HTTPS was an implication that the governments mentioned didn't need to get those companies (such as anti-virus companies, etc) to scan for [insert scary material here] as they would have just been able to hoover it up on the wire (as was shown happens in the US by Snowden)
Thus the question of "Why haven't those vendors been already co-opted by governments" is answered IMO - it wasn't necessary.
Edit: to be fair - i now see what you mean - "never leaving the device and still getting scanned" vs "scanned in transit"