I think it's a sweet spot. For $9 a month my wife and I don't need to discuss it. For $30 a month recurring, one we'll discuss it, and two, we'd better see a lot of value.
The price is at a point where even if we're busy and don't watch more than 1 or 2 movies that month, we won't mind, because of the convenience of having them instantly available via streaming, and knowing that the price is low.
It's low effort, high convenience.