CAPTCHAs can protect public resources as well. But the main problem here is about preventing generated spam content, not scraping. This can be mitigated by placing CAPTCHAs only on pages with signup/login and comment forms.
Traditional captcha solving ability has already been surpassed by the bots which is now why there's so many new and creative different CAPTCHAs. Until someone trains a model to solve them that is.
>This can be mitigated by placing CAPTCHAs only on signup/login and comment forms.
If only...
Algorithmic turing test is a more interesting problem. https://xkcd.com/810/
Traditional captcha solving ability has already been surpassed by the bots which is now why there's so many new and creative different CAPTCHAs. Until someone trains a model to solve them that is.