On one hand, since you are not suffering from disease and famine on every hand, and your peasants are not thin as posts, hollow-eyed and exhausted and ancient at forty, having buried eight of their ten children, you probably have good solid workable magic that produces a good solid prosperity.
On the other hand, kings, queens, princes and princesses, dukes, counts, and other nobles. . . .
Wealth and prosperity produce leveling tendencies. For one thing, they produce people with time on their hands when they are not so stupefied with exhaustion that they can't think about social rising. In the Dark Ages you had men who worked, men who prayed, men who fought -- and then with improving travel conditions, you started to have the problem of merchants, who are hard to dismiss 'cause they've got the money. Some writers even divided up society into four classes. The knights started to be knighted, to differentiate themselves. (Counterproductive, that, because a fat merchant can be knighted much more easily than he can fight in battle.)
Or again, let us get to a Victorian level of magic. Much of the Victorian rigidities about class were the knowledge that it was, in fact, very flimsy, and rising was much easier than it had been. Compare Shakespeare's plays to Gilbert and Sullivan's. The clown could marry in a Shakespearean play, but only to a woman of his own station, and vice versa. Yeoman of the Guard -- it would never even have been suggested that the Colonel marry Elsie if it were a Shakespearean play. Or the whole social class rigamarole in HMS Pinafore.
Now, your Standard Fantasy Setting has a magic level equivalent in many ways to a late Victorian technology, or even better. Agriculture and healing in particular. Yet, you keep the hierarchy.
Then, perhaps the magic is driven from the top-down. If you had a Fisher King effect on the land, and the effect sprang from spells, those in power would have a good grip on it. Especially if the spells required rare ingredients, or specially constructed tools. (And they would, of course. The Law of Similarity decrees you can't get extraordinary effects from ordinary means.)
Might still have to be permeable.
Though I was thinking about it in terms of Oz -- creating a trivia question on goodreads, for why the Deadly Desert is just a large desert in The Marvelous Land of Oz, and actually poisonous in Ozma of Oz. Creating wrong answers for the multiple guess, I put down that it changed because Ozma was enthroned, and the land reasserted its magic. You could have some real fun with defenses like that.