It probably doesn't apply to Black Mirror, but you can do real worldbuilding in a show that goes 25 episodes/year that you can't do in 10 episodes. And some sho

It probably doesn't apply to Black Mirror, but you can do real worldbuilding in a show that goes 25 episodes/year that you can't do in 10 episodes. And some shows/genres really benefit from that, becoming something more than the sum of their individual episodes. Many modern shows miss out by rushing through a self contained story in a short season. But if I understand Black Mirror correctly, it's an anthology without a shared world/characters. There'd be diminishing returns much sooner with additional episodes. There's only so much to say about that theme. And we're living it every week anyway.