You Pay for the game overall not just the dungeons. As people said you don't have to wait to play the game ever, You in a queue for a dungeon go do something while you wait. There are plenty of things to do in this game. Fates are actually quite fun.
Edit: Also a counter to that Car analogy: I don't know about you but I wait in queues to drive my car all the time. It's called traffic, other people wanting to drive their cars can definitely cause me to not be able to drive mine the way I want. No worries though like this game cars offer other things to do while you are in the traffic queue. Look out the window to enjoy scenery, listen to the radio, etc.
