They WILL advertise. Just not via ridiculously-easy-to-block 3rd party javascript streaming ads. If the ads are displayed by the same method as the content, then they are obviously unblockable.
Sites will instead become a direct seller of the commodity of time units of ad space. The buyers will be advertisers. How can commodities be efficiently allocated between many buyers and sellers? It's called a market. If you've read one economics book you'll be able to come up with 10 possible business ideas from here.
Those same economics books also will show the inevitability of middle men. The internet started with exactly the model you describe and evolved to it's current state. Expecting it to devolve back down is not a strategy I would back.
Correct by posting these comments I have been promoting the idea of middle men such as ourselves to create ad markets for direct participation by buyers and sellers (individuals and firms). I meant that the flavor, i.e. whether modelled after matchmaking services, auction sites, or the stock market doesn't matter there are plenty of options for ideas that could work.
Full disclosure: I currently although not for long work on the Google Affiliate Network which pretty much does exactly that. Most affiliates host the ad themselves.
Sites will instead become a direct seller of the commodity of time units of ad space. The buyers will be advertisers. How can commodities be efficiently allocated between many buyers and sellers? It's called a market. If you've read one economics book you'll be able to come up with 10 possible business ideas from here.