A lot of "netflix users" are middle and high school age kids in third world countries using a borrowed account. User context matters a lot. If someone's friends-friends-friends uncle changes their password, it's no surprise those "netflix users" would switch to an ad-supported model. It's possible but unlikely the 12 year old kid watching anime on a shared/borderline stolen account has the resources necessary to buy an ad free account at US prices.

But the ad-supported tier isn't free either.

I don't think the difference for a 12yo is $7.99 for standard with ads vs $17.99 for standard.

It's $0 vs any non-zero dollar amount.