Plenty of people are doing click fraud. It takes some effort, its not just push button receive ill gotten gains, but it works. It is just not nearly as lucrative as other methods of driving illegitimate traffic nowadays, because most people dont do pay per click.

I dont have a spam website to push, but I know people who were making anywhere from 1-3k a month based on exploiting different advertising rings looking for traffic. Usually they would setup a campaign with an advertiser and wash dirty traffic that they were buying through the advertiser's site, paying 1/10-1/20th of the cost of each conversion or click, and most of the time those would just be botnet operations anyway, they didn't care.

It usually doesnt last long per identity, but those are a dime a dozen.