You seem to consider the consumer the only “agent” — they have to make the decision on what sites to visit, they have to comply with the terms of the implicit agreement... what are the obligations of the publisher?
A publisher chooses what to publish. The agent chooses what to consume, on the terms specified by the publisher. If they don't like those terms, they don't consume. If publishers don't get enough consumers due to onerous terms, they relax their terms. That's how our system is supposed to work.
But couldn't this be framed as: the viewer chooses what to request. The agent chooses how to respond, based on the terms offered by the requestor. They could require a payment, a login, or a promise to view ads before responding.
