Google's reCAPTCHA v2 just labor exploitation, boffins say - theregister
Web puzzles don't protect against bots, but humans have spent 819 million unpaid hours solving them
I don't know, it is clear that Google is getting free labor out of users solving their captchas.
However, I disagree with captchas being ineffective. If captchas were so ineffective there won't be sites dedicated to having people in developing countries solve them.
It is very easy to make a script that makes accounts by sending post requests without captchas. It requires little skill. You can see this with new lemmy instances being filled with spam until the admin adds a captcha or questionnaire.
By following links in the article, one reaches https://arxiv.org/pdf/2307.12108, which includes the table:
The claim of the story is not that CAPTCHAs have zero effect on a website (they obviously do ward off against casual "attackers" and also obviously cause some legit users to abandon the website).