I also keep thinking about this in terms of The Good Wife spin-off. Now, Discovery, unless it's really and truly terrible, I will be there watching it right away every week, because I am an insane Star Trek fan.
Good Wife, I am not a crazy fan, but I liked that show (most of the time -- but this isn't the place for that rant

). I'm interested in checking out the spin-off. Probably even enough to sign-up right when it starts in February and check out the pilot. But am I going to be interested enough to make a point to keep ahead of expiration dates as the season progresses and I'm juggling a million other shows and everything else in my life? Probably not. Tracking that sounds like work. That's a reason to cancel. But the episodes piling up, waiting to be watched whenever I find the time to take them in... that's a reason to just let it keep rebilling forever.
Streaming is in some ways like the business model of a gym. Yes, there's lots of avid users, and many money-conscious customers who would cancel the minute they know they're not going anymore. But there's also a TON of people who sign up and never/rarely use it, but believe they're perpetually ABOUT to use it, so they just let it rebill the modest cost every month. Companies know there's a lot of these inertia consumers out there: just get them to sign up once, and either their laziness or their distraction with life will keep them paying a monthly fee for a long time -- as long as you don't actively drive them away.
This is the whole reason to produce your own shows for your own streaming service -- you can keep it up there forever, perpetually adding value for your subscribers, and you don't ever have to negotiate with anyone else who owns the show and can yank it away if you don't agree to their terms.