Then they will simply solve the captchas using captcha solvers or humans paid pennies per captcha. You do something else and the botmasters will respond.

It's really hard to get rid of bots and fake accounts. Also, false positives are expensive because you end up annoying a real human and as a result your mistake doesn't disappear until you make it right.

The cat and mouse game of bots vs captchas has been going on for a long time and has become increasingly sophisticated. "Just use a captcha image" is a 10 year old solution, if not more.