On YouTube I reported bot accounts for a couple days, the only reaction I got was that at some point it showed a popup that told me too many false reports would lead to a ban. Not sure what Google gets out of it, but there is no way they could be that bad at fighting bots unless they're not even trying. Even trivial tricks like copy-pasted texts keep working.
Google makes loads of money through scam ads and fake/AI slop videos. Anyone trying to get in the way of that is putting Google's profits at risk, hence why they shut down legitimate accounts but scammers just run free.
Bot comments and uploads count in KPIs. Blocking/Removing bots = KPIs look worse.
They're not trying. I've seen an advertiser remain active for months with literally tens of thousands of ads where clicking them directly downloads a malicious exe file that most antivirus scanners flag.