Captchas are already being broken
Captcha's are at best a temporary solution to a long term problem.
I've followed this topic for a long time.
Do a search and find hundreds of links about breaking captchas.
Some engines are generic enough to work with many captcha generators.
To respond to this threat, sites make the captchas more and more difficult to recognize to the point where I personally make mistakes when I incorrectly guess what the correct answer is. I imagine an automated program may have a better chance at solving these than I do.
In any case it was long speculated that it would always be possible to pay people to manually solve the captchas.
I would like to see more effort to block spammers at the point of origination.
For instance, apply spam heuristics on a sender's email and take action earlier.
If thousands of accounts are sending the permutations of the same email, then there is a very high chance that it is spam.