I can’t think of any other devices that have apps in the same sense where other developers can also release their apps as long as there is a cut for the platform holder where there is no other legal alternative to get apps elsewhere.

The only examples I can think of are games consoles, but they are seemingly next on the chopping block. I think the only thing that has stopped that from happening as soon as the apple one is the fact that for the majority of games, you can still get them physically elsewhere at prices that aren’t completely dictated by the platform holder.