There is a specific reason for this.
The scammers are repeat players. They have a thousand accounts, three quarters of them get shut down, they look at the other 250 to see what's different, make 1000 more accounts that look more like the ones that didn't get shut down, now only half of them get shut down and they get even more data on how to avoid getting banned.
Meanwhile the ordinary user has only one account, maybe two or three for small businesses and things. If one account gets shut down their life is disrupted and they have no idea why it happened or what to do about it or how to avoid it happening again.
Google have to shut down 1000 accounts for this one scammer and if they get 999 of them right and 1 of them wrong, the scammer still has an account and the honest user doesn't.
The real problem here is that we're expecting Google to do this instead of law enforcement. Is there a scammer? Arrest them. They can't make 1000 more accounts from prison and then Google don't have to play whack a mole while clobbering tons of innocent people.