[Asquil]

Dollar per hour is not necessarily a good metric, but it is a metric. And we need a metric like that to quantitatively compare different mediums.

What you say about the complexity of entertainment is absolutely true, but we somehow need to model it in a relatively easy way, and that means throwing out some details.

And from in naive guess, people don't enjoy themselves significantly more watching film than playing videogames. So dollar per hour is a good enough metric for our purposes.