The probability of you cancelling Netflix in a given month is inversely proportional to the amount of Netflix you or your household watched [1]. The expense of a marginal delivery of a particular episode's worth of resources is a great deal less for Netflix than the revenue of your subscription.

[1]: To a first approximation, anyhow. I bet there's a bump at zero, where people just entirely forget Netflix exists but they are still subscribed. If someone watches a single thing a month they're probably more likely to eventually realize they're not using it enough.