If people are willing to consume content but not willing to pay for it, then you have a very strong indicator it has no value at all and therefore no actual need to be produced in the first place.
Or at least, not enough subjective value for that person to outweigh the cost. Paywalls are a great screening filter that actually tests if people want to spend any money or time on an article, or merely clicked through from force of habit.
People willing to pay by consuming ads are indicating the content is worth that price - to them. The fact such people exist is proved by the fact such sites exist.