It's probably got something to do with copyright. Like the way it interacts with markets makes this sort of arrangement net-harmful pretty much any time you see it.
I would say it is monopoly.
If you are a luxury brand you may sell your pen in a brand store only and limit access and will have some business.
But other companies will produce comparable pens and then your only moat is the brand identity but in all objective criteria the other pens are equal.
With intellectual work you got the monopoly. If I want the Taylor Swift song I don't want Lady Gaga, even though both may be good. If I want a Batman movie, I don't want Iron Man. These products aren't comparable in the same way. And another vendor (studio) can't produce an equal product in the same way as with the pen example.
The thing to understand is that the benefits of competition isn't price. It's innovation. Sometimes that innovation is how to make a component cheaper but other times it's new components. The iPhone was not the cheapest phone when it was released.
Do Porsche dealerships have a monopoly on Porsches because only they sell Porsches, and you want a Porsche from somewhere else?
If Porsche were to do that, a lot of customers would probably switch to BMW or Audi instead. But with Movies and TV, competing products are less fungible.