Kernel spyware is at least 2 decades old, and manual scrutiny of casual participants is as old as networked competitive gaming and cheating themselves (id games had that from the start!). It has nothing to do with money. Moreover, people are paying north of $1k/mo to cheat in video games.

I remember watching Counterstrike tournaments in CPL in the early 2000s and Intel Extreme Masters in 2007.

LoL (Riot's first big "esport" game) didn't really start having large tournaments until 2011. LoL didn't even come out until a few years after ESL started hosting regular professionalized Counter Strike tournaments.