That's what I was thinking. Originally reCAPTCHA had the control word be a scan as well, which meant that an attacker had to beat their OCR. Now that the control word is computer generated, the system has devolved into a regular CAPTCHA that further asks humans for recognition task work.
This version no longer advances OCR algorithms, but does provide cheap exception handling. I don't know when or why the change was made, but obsolescence is at the top of my mind. Either they've ran out of unrecognized words, or adversaries have beaten their OCR. Either way, it seems we're back to 2005.
edit: That said, Luis von Ahn mentioned that Google is experimenting with other image processing tasks, so there's hope yet.
This version no longer advances OCR algorithms, but does provide cheap exception handling. I don't know when or why the change was made, but obsolescence is at the top of my mind. Either they've ran out of unrecognized words, or adversaries have beaten their OCR. Either way, it seems we're back to 2005.
edit: That said, Luis von Ahn mentioned that Google is experimenting with other image processing tasks, so there's hope yet.