The other problem is that I think the cost of someone using a subscription service will be higher than the average moviegoer, simply because going to the movies often is cost prohibitive for a lot of people.
Maybe it's a matter of just not allowing subscription passes for opening weekend (or only at the door if it's undersold rather than in advance). Maybe you get your seat allocated at ticket pick up rather than in advance so full-fare paying customers get the best seats. There's obviously going to be a compromise somewhere, but it doesn't have to be unworkable.
Percentage of revenue, i.e. per ticket sold [1]. That said, the studios' take rates vary "as you move into the second and third weeks of release," when "the percentage starts to swing to" a greater take rate for the cinema. A movie pass which blacks out the first N weeks after release could thus be economical (if something the studios would fight tooth and nail).
The unit cost of one person in a cinema is normally negligible after all, so a specific cinema just need to convince members to spend a little more, and to always spend it at their cinema. Moviepass does neither of these things.
This is definitely a model which can work for cinemas. Just not at this price point and business model.