Think of it as a perpetual bond with declining coupon payments.
Customer "inertia" or "lock-in" might be better terms to describe what the company is looking for in an acquisition.
Their ideal customer may well be someone who's forgotten they have a subscription on credit card auto-pay.
> a perpetual bond with declining coupon payments
Most things with royalties (oil fields, songs) work like this.
Add to this that they make it really, really hard to unsubscribe. I think there's been some legal crackdowns, but for a time, they could make it literally impossible.