Common wisdom does not account for that some cash cow keyword/adnet combination you can approach to 90% of traffic coming from bots, or conversions being near nil even without clickfraud being involved, or for ad nets having interest to actually go soft on clickfraud.

Whenever I worked in media agencies, I do see people running digital ads for major brands (coke, nike, li ning, microsoft level) being at least moderately competent in technicalities, yet I can't say that any of them ever approached to even partial understanding of what a total "Wild West" is the online ads industry today.