I presume by "defeat" they mean "use one of the libraries that allows you to pay $0.10 for each query, to route your CAPTCHA to people in developing countries who will solve them for you." Which is economically viable for individual use-cases, but still economically unviable for spambots.

It is much cheaper than 0,10 USD per captcha.

Another technique is to enable the accessibility mode, which is a speech-to-text prompt and is supposedly easier to bypass.

It would still limit "most" =p

Spot on!