While I agree that human labor is thousands of times slower and thousands of times more expensive than an all computational solution that is not the point most

While I agree that human labor is thousands of times slower and thousands of times more expensive than an all computational solution that is not the point most of the time for automated systems. In the case of messages and wall post on Google or Facebook, once a CAPTCHA is solved you get to send N messages before the next one is popped up. Without the CAPTCHA you could only go so fast anyway due to general rate limits so the impact on spam, for either service, is minimal. In the case of account creation in general the limit for automated systems is more heavily dependent on diversified proxy access more than anything else. Additionally, you can only effectively manage so many accounts at one time depending on your needs and CAPTCHA do not add more than a few % time delay to the overall account creation process.