Earlier quoted context omitted.
If you divide US digital ad spend in 2016 by number of US households, that's about $50/month. Same order of magnitude as my earlier guesstimate.
Sure but that's a very indirect calculation. Only a fraction of that is going to end up funneled to banner ads and the websites that run them. And that's the relevant metric; how much revenue you are losing by moving away from ads.
But then we have to consider that 95% of the costs/fees for running ad networks would still be needed for cost-sharing models too. You still need third-party JS.