They could also easily block known VPN IP ranges (they don't). Netflix generally is not (yet) user unfriendly. There are myriad ways of buying a subscription,

They could also easily block known VPN IP ranges (they don't). Netflix generally is not (yet) user unfriendly. There are myriad ways of buying a subscription, including gift cards, third party tie-ups etc, it won't be easy to implement a fool proof solution which works for all of them, especially without degrading user experience. It is more likely that problem is not big enough for Netflix that it wasn't worth investing that kind of effort. Similar to how they are handling password sharing now, it is perhaps possible they will look into this in the future as margins tighten and pressure increases as they keep loosing subscribers to competition.