There is something really, very deliberately screwy with the writing in DA games regarding how mages are shown.
You have mages who want to get so badly they’re willing to turn to demons and blood magic. You have mages like Finn and Vivienne who say that, pffft, getting a pass is easy and more mages should just do that instead of going crazy and banging against the walls. You have Templars who tell you the only way out is to jump out the window (and according to them that some mages have tried that), and you have Knight-Commander who says that First Enchanter has the final word.
Those towers remind me of feudal city in Thedas. There are lines between people, slums and nobles of mage tower, Templars acting like a city guard with curfew and a permission to kill if necessary, mages at the bottom of the ladder who will never go out, and mages like Vivienne who know how to play the game and will get what they want. Even locked away connections are everything, unless your Knight-Commander is Meredith.
In theory, getting a permission should be easy if you’re a good little mage and it probably was in the early days of the Circle – in practice, not so much.
Mages are far from equal in the tower. If you do not prove your usefulness to the Circle, if you do not know the right people, say the right words in the right ear, or even share someone’s bed if required, you will never go out.