> You can implement basic defenses like hidden input forms or checkboxes that are masked by CSS rules or served on the client side with JavaScript to weed out bots from human users, among other less intrusive techniques.

Umh, anything that will end up in the POST request will be reproduced by a bot, I don't even actually look at the page when implementing screen scraping modules, but just at the Network tab of the Chrome Dev Tools.

What I think have the potential to remove the need for conscious CAPTCHA solving is what Google is supposedly doing here: machine learning on behavioral patterns in the user interaction with the form (instead of just with the CAPTCHA).