You are referring to license monopoly. There are actually three kinds of local monopolies: margin monopoly, limited-space monopoly and license monopoly. Von Mises does a very good survey of these types of monopolies, monopoly prices and the conditions under which each exists [1]. Von Mises is a very deep thinker on this topic from a classical liberal perspective. He does agree that monopolies exist, but takes care to define the conditions under which they can exist. If a government wants to provide the best competitive environment, there are steps that can be taken to mitigate monopoly conditions from arising.

[1]. https://mises.org/library/human-action-0/html/pp/764