They're not free-riding currently, but what the parent is suggesting is that streaming subscriptions don't charge for months without activity.
> Usage based billing isn't that hard. It's just less profitable.
Creating alternative usage-based billing models when most customers are happy with a monthly model is hard and has real costs. There are already storefronts with a more usage-based model: stuff like iTunes and Google Play Store let you pay per movie & episode, that's typically what consumers use when they don't like a monthly billing model.
But, by that same logic, they should just be charging you by how much you watch. So it's no longer "don't charge them for the month they didn't view" but, instead, "charge them $X/minute watched". If you're going to go with usage based billing, go with usage based billing.
People who fail to cancel their subscriptions are not free-riding off anyone, they're paying $X per billing period.
> Asking central organizations like a corporation to infer the correct thing for lots of consumers is very difficult and costly
Usage based billing isn't that hard. It's just less profitable.