And as bad as click fraud on Google and Facebook is, I don't see how more advertisers would help. The only way they could really improve fraud detection is if Google Analytics were instead some sort of public utility. And even then I don't really see how you could get a competitive marketplace for fighting fraud. You would just have to trust that the analytics utility was legit.

And anyway GDPR/CCPA type legislation is probably a better route, which if anything makes fraud detection even more difficult.