The exact company you're asking for existed already, almost two decades ago. It was called Project Wonderful, and initially focused on independent blogs and webcomics.

https://en.wikipedia.org/wiki/Project_Wonderful

It never managed more than modest success and never expanded far outside its initial sphere. It shut down in 2018 because it was unable to compete with all the monopolist walled garden ad spaces.

There are various small projects that could claim to be successors to that ethos -- but (to a rounding error) no one has heard of them because, contrary to your claim, the revealed "premium" that users place on "quality ads" is dwarfed by the premium that advertisers place on aggressive attention vampires (and the latter are the ones actually paying)

Can you share some names? Would be interesting to check them out.

I understand why such a company will never make big money, but I don't see why it couldn't operate and survive. Running a small-scale ad network incurs small-scale costs. I guess the problem would burnout of people maintaining it.