This sounds completely reasonable to me, and I don't know where it's wrong, but it doesn't square with my experience and I think it's wrong.
If this were true, nobody would be getting mad about ad blockers. But both advertisers and publishers (big and small) regularly complain about ad blockers, and even with a relatively small portion of users installing a blocker, multiple journalism sites have started adding paywalls. This paranoia isn't restricted to small sites either -- Google's even listed ad blockers as a potential revenue problem in investor disclosures.
A couple of potential causes: maybe it's that impressions actually do matter to revenue in some cases and we haven't completely moved over to conversions yet, or maybe it's that advertising increases consumer spending even without direct conversion rates, or that most publishers are engaged in fraud and ad-blockers make it harder to do that. It might even just be that publishers/advertisers are all stupid and haven't realized that ad blockers don't matter, but I think that's unlikely.
What seems plausible to me is that most of the people who block ads are not as immune to advertising as they claim. If they didn't block ads, they would occasionally click on an ad and provide a conversion. I would not be surprised to see that exposure to advertising increased overall spending, and didn't just redirect it to specific companies. I could be wrong though, maybe it's something else. I'd be interested to see research on that kind of thing.
Regardless, it is very difficult for me to square the world you describe with a world where a huge fraction of news sites I visit are including banners that tell people to whitelist ads, or anti-adblocking technology outright, or are just giving up and switching to subscription models. I can't think of an explanation for that other than, "ad blockers decrease revenue", and I think that having an explanation for that behavior is a prerequisite to making a believable claim that ad blockers aren't hurting revenue right now.
I mean, Google's not dumb. They would not have wasted time on the acceptable ads initiative if they didn't feel like they needed to.