Google doesn't make money from reCaptcha[1], and reCaptcha isn't deployed to stop the kind of crawlers Google operates (you'd just add a line to robots.txt if you wanted to do this), so I'm not sure how this is relevant.
[1]: OK, maybe in the extremely broad, indirect sense that reCaptcha helps Google solve image classification problems, which make Google products like Maps/Books/Images better, which increases traffic, which increases ad revenue
[1]: OK, maybe in the extremely broad, indirect sense that reCaptcha helps Google solve image classification problems, which make Google products like Maps/Books/Images better, which increases traffic, which increases ad revenue