The web as we knew it before ChatGPT was built around the idea that humans have to scavenge for information, and while they're doing that, you can show them ads. In that world, content didn't need to be too protected because you were making up for it in eyeballs anyway.
With AI, that model is breaking down. We're seeing a shift towards bot traffic rather than human traffic, and information can be accessed far more effectively and, most importantly, without ad impressions. So, it makes total sense for them to be more protective about who has access to their content and to make sure people are actually paying for it, be it with ad views or some other form of agreement.