Our niche is office design content and we sell advertising primarily to office furniture manufacturers. The ads are hosted by us and are sold directly.
This approach definitely works, and I agree you can do it without any tracking. All that's needed is that the furniture manufacturers can tell how much of their purchases are coming via your site.
But this is also not a model that can support a very large fraction of the existing web. Most sites aren't built from the ground up to have this kind of highly commercial tie-in.
We partially do something similar. I wrote an adserver that mainly serves contextual ads. We also serve consent-requiring ads if given, but with an adblocker (a bespoke adserver for a smallish site rarely gets blocked) or no consent, we serve HTML ads based on context.
But this is also not a model that can support a very large fraction of the existing web. Most sites aren't built from the ground up to have this kind of highly commercial tie-in.