The game isn't between the host wanting to push ads and the client wanting to block ads. It's a 3-way conflict between the client wanting to see the fewest ads,

The game isn't between the host wanting to push ads and the client wanting to block ads. It's a 3-way conflict between the client wanting to see the fewest ads, the advertiser wanting their ads to be seen by the most clients, and the site host wanting the most ads to be seen by each client. And neither side trusts either of the others. If the entire transaction was only carried out between the site and the client then the advertisers would have to believe that the reports being delivered to them by the site owner are accurate. And they know from experience not to believe it. So they insist on having clients tracked themselves or by a third-party (fourth-party?) which is where all the complicated connections, alternate domains, and bloated Javascript come from.