I created a tool that automatically follows ads to try to find scams.

But that was usually reserved to typosquat domain ads or ads on porn websites. I didn't know scammers used normal page ads too.

I know tech support scams used to use google search ads, but I don't think they do that as much anymore, so maybe they have moved onto things like adsense.

These scammers usually do IP address checks to check for residential IP before showing the scam, and some also do some basic fingerprinting checks, so that is how they get past detection. That said, it shouldn't be too difficult for google to do some better checks if they actually cared.