I'm looking for a way to watch recent Nebula plus videos. I only have two short videos that I am looking to watch and I don't think that justifies the cost of a subscription, though I would gladly pay 50p for each video.
Think about how this would actually work. Suppose you paid some small sum for access to a piece of content.
Fairly speaking, you should only get one chance to download it or one physical copy. That's how it's traditionally been. The ability to download it multiple times (which is what happens when you stream content) is a service, and it costs a lot of money.
Streaming would therefore be pay-per-view, since you are paying for each individual copy of the data that has to be transmitted to you. It wouldn't be fair for you to just pay once and watch once and have paid the same price as someone who paid once but watched it fifty times, thereby consuming fifty times as much server power.
Most people would find it more convenient to pay a large sum upfront in exchange instead of going through the hassle of making dozens of micropayments.
In order to encourage people to make those large upfront payments, content creators would probably offer deals whereby users could get unlimited streams of their content if they commit a certain amount each month. This means their revenue is predictable and the expense is also predictable for the viewer.
Congratulations. We have invented the pricing scheme of cable television.