The purpose of recaptcha is to block malicious bots from accessing parts of a site that automated bots are not supposed to go to.
Why would someone be using recaptcha to block bots from the general part of their web site? Your imaginary scenario would require web masters to become hostile to crawlers.
You must have been living under a rock for the past decade, haven't you? Web masters are definitely hostile towards webcrawlers. There's an entire platitude of "web-crawler" protection services - cloudflare for example is probably the biggest one.
Why would someone be using recaptcha to block bots from the general part of their web site? Your imaginary scenario would require web masters to become hostile to crawlers.