Why all the Chinese comment spam?

This may explain why CAPTCHA is unable to keep the Chinese comment spam off of my blog -- Chinese sweatshops are full of workers who are paid to post this spam. What confuses me is that Google has not elected to harness the power of these spammers by using Re-CAPTCHA.

from CAPTCHA Economics at Marginal Revolution:

Bottom line:

• Prices run about $1 per thousand CAPTCHAs solved, depending on the time of day and demand.

• The median response time to solve a CAPTCHA is 14 seconds and accuracy runs about 90%.

• "[T]he business of solving CAPTCHAs,...is a well developed, highly-competitive industry with the capacity to solve on the order of a million CAPTCHAs per day."