When I forget to sign in to YouTube, I see the same pattern, shitty ads that are clearly only allowed because otherwise YouTube wouldn't have sufficient ad inventory to meet their internal KPIs.
The reality is, of course, that Google and its ilk doesn't give a single rat's ass about people falling from scams or getting infected by malware. Scams and malware pays better than "ethical" ads (to the degree that such a thing exists). It's a travesty that there are apparently no laws against their behavior.
For the bulk of legit advertisers, this won't affect the bottom line of a given campaign and will keep out the scammers, etc. Leading to a much higher quality ecosystem. It would also give Google the potential for a higher percentage share of profits in the system. It would also likely reduce the CPM pricing though, possibly to a larger extent than profits from the validation system itself.
But it would be a much healthier overall system.