Also, people are probably not going to go out of their way to tune their spambots to work on a personal blog that's just one of a billion tiny little targets, s

Also, people are probably not going to go out of their way to tune their spambots to work on a personal blog that's just one of a billion tiny little targets, so something like a static "CAPTCHA" makes sense. But grandparent implies that this extends to the websites of large companies for which people have a lot to gain by creating specialized bots, which is pretty obviously not true.