Or the perfect subscriber
Netflix can only get so many subscribers. Imagine for a minute that they get all members of a nation to subscribe. That means, they would have reached their maximum level of solvency. But because of the nature of market forces, at least in the US, Netflix has to continue to grow. They have to increase revenue every month, or at least show that they are working on a plan to increase it.
When you can't increase revenue, no one else to sell to, the obvious thing to decrease cost. Netflix does spend a boatload of making new shows. They will reach a limit, and their only option will be to decrease the cost of those shows. And hopefully maintain a similar quality. But you can only save so much by cutting costs before your customers start noticing. At the threshold, customers will stop paying you.
Another option will be to save on bandwidth, by decreasing the number of servers you have running. But a buffering video will lead customers to a more reliable service.
Ads can increase revenue, but customers that are already paying premium won't be happy. They are paying specifically to not see ads. Now you've given them a reason to leave.
These are three problems that a customer can face that will lead them to your settings page and hit that "Cancel Subscription" button.
The ideal Netflix customer should be one immune to these three problems. This customer does not care about the quality of your movie. High budget, low budget, no budget, it doesn't matter. At the end of the month, they pay for their subscription.
This customer does not care if when they click on a movie it instantly starts. If the movie buffers every 5 minutes, they don't care either. In fact, if they check the service and it says "Come back tomorrow," at the end of the month they will renew their subscription once more.
This customer does not care that the movie is now interrupted by ads. In fact, he doesn't even care that you increased the cost by 20%. They continue to pay consistently. This is the customer that will help Netflix continue to survive in a market that they have completely dominated.
This customer has simply forgotten that he has a Netflix subscription. He consumes no bandwidth because he doesn't even know he has the service. He doesn't mind the ads, because he doesn't know there are ads now. He doesn't care that you use cheap unconvincing VFX in your shows. He doesn't care that all your actors are C list. He doesn't even care that you are charging his card every month.
This is the perfect Netflix customer. In our algorithm driven times, a formula will be developed to make us consume less without ever stopping our subscription. Planet Fitness does the same, they are happier when you pay and don't show up. Manscaped does the same. And every subscription service will look for a way to get you to forget about them.