> There is no such thing as "ad provider."
If a website serves me malware, the website's owner should be liable to me. They may then be able to sue someone else, in turn. But I chose to interact with them and then they chose to outsource stuff to crooks.
This would be complicated to implement. But it's absolutely doable.
No, it's not. It completely upsets the economics of content management and makes it absolutely impractical for content owners to monetize through ads. No ad revenue would be worth such liability.
Then there are all kinds of fun scenarios - from drive-by malware to landing page malware to malware served after clicking an ad ON A LANDING PAGE. Who would assume responsibility for those?
Bottom line, this is not much different from "regular" crime. It happens. Governments employ police and various deterrents to reduce it. But it doesn't relieve you, the citizen, of responsibility to be mindful and exercise situational awareness.