You're right, and you bring up a good point. Almost nothing is free, and there is always a cost. So it makes sense that ads started coming into the web in the beginning, so that people might click them and people who hosted the content might get money that way. However, nowadays, that's not enough. There's usually more than just one ad.
Obviously my comment was the "cynical" view, and looked at a future that may not even come to fruition. There are some benefits too. However, I think that I would prefer that the web be supported in different ways. I haven't thought long and hard about the "best way", but it makes me think of websites that limit how many times you can view their content. Take the New York Times for example. If I remember correctly, they let you view ~10 articles or something, and then from there, you have to pay to see more. That could be a potential way to keep content supported? Let the websites choose themselves how they want to monetize content. Maybe that's better than Google holding accounts for anyone who wants to access the ad free web? I'm not sure what the best solution is.
In the fantasy future I mentioned in the first comment, I could see there being a pay-to-entry model for the web, if the ad free and ad versions of the web started separating and they just "killed" off ads. Then, to access the web in the first place, payment would be required, and would have to be refilled.
This is one reason I love HN - discussions get me thinking. I appreciate your comment, and you're right. All content just can't be free. I guess I just don't like the possibility of the web turning into a pay-to-view model. I'd rather let the sites choose individually, that way, no one has control over it all. But yeah.