Between captcha load, post and post reply, you already lose 1 second!
If 60 seconds = 1 minute, and you lose 1 second with load/reload of captcha, how many captcha can you generate in 1 minute?

Simple math!
The captcha limit per minute is 30! Regardless of whether the wiki says 120, you will not be able to do more than 30, even if you get the miracle of responding 30 alphanumerical and distorted captcha on miliseconds, the system will not respond to you at the same time.

I am not against use of automation systems.
The problem is that these people who are using, are abusing the faucet.