Most people are probably lazier and less organized than you give them credit for. If subscribe/unsubscribe cycles were really that prevalent I think you'd see a lot more incentives to sign up for, say, annual subscriptions.
A lot of people basically use TV as background and, especially if they don't have live TV, that means a lot of streaming content.
People don't need more than one streaming platform for "background noise", and switching to the one with the most popular shows of the month makes a lot of economic sense. At the end of the year, it can easily save you hundreds of dollars, and the bigger the amount, the more people are going to do the maths.
Maybe an annual Netflix subscription is planned.