What nonsense. Most content's worth is variable depending on who is consuming it. The issue with ad-blockers is that it isn't killing worthless content. It's killing content that survives between the insane traffic of Facebook and the complete lack of traffic in personal blogs that 12 people visit.
> The purpose can easily be filled by some alternate, free material.
Yes, because the quality of content supported by ads and the quality of content done by some ad-free blog in someone's free time is always equal.
> When the content can be easily leveraged to some profitable goal, people are usually more than willing to pay for it.
You mean like instructional YouTube videos, free web-based resources for learning new things (programming, languages, etc). Oh wait, all of that is ad-supported.