I do wonder, clearly there is a perverse incentive for YouTube to be less strict with ads, but is it also a question of availability? I've been paying for YouTu

I do wonder, clearly there is a perverse incentive for YouTube to be less strict with ads, but is it also a question of availability? I've been paying for YouTube Premium, so haven't seen ads in a while, but before that I noticed that there was almost no variety in the ads. You just got the same three or four ads on repeat. What I'm wondering is: Does YouTube not have enough quality advertisers? You'd think they'd turn away the scammers, because actual business doesn't want to be on the same platform as some shady "buy/sell gold" or similar. If they don't, is that because there's no money, or not enough honest business buying ads in a sufficient amount? Or is it that YouTube just makes more on the scams?