Possibly: it's not fully clear yet whether the GDPR requires you to offer people the opportunity to use your site without ad fraud detection, but I'm expecting it turns out it does. And without ad fraud detection ad-supported sites are mostly not practical.
You can have ad models that are immune to fraud. A time-based model such as "your ad here for X days" is immune to fraud, just like ads in print or TV are immune to it. If the ad drives purchases, the advertiser renews; if it doesn't, you may have to lower your price until another one comes up.
It's not immune to fraud: if I offer you ad space on jefftk.com how do you know how much to pay for it? Without some kind of fraud detection, how do you know whether to trust me when I tell you I have 25k unique visitors monthly?
Could always be an auction-based market - you start with a trial and only do a day/week/etc and gauge your results - if they're good you know you can bid more next time. With enough "liquidity" on either side the true price of said ad inventory will naturally come up without any tracking necessary.
That works for performance advertising, where you're able to tell whether your specific ad is getting results. But most display advertising (by dollars) is brand advertising, where Ford cares that a real person is seeing their ad but isn't expecting you're going to drop everything and click through to buy a truck.
How has that problem been resolved in offline (print/TV/display) advertising be solved, and could those solutions be reused for the web?
It seems like the free-for-all with regards to personal data and decriminalisation of spyware has led the online ads market into a near-optimal situation with regards to targeting & fraud detection, but 1) is it a trade-off people are willing to accept (the GDPR being enacted suggests not) and 2) can there be alternatives that give both sides what they want?