What does a wizard do in order to establish themselves in the world? Why are they wondering the world with the rest of these rag-tag adventurers? With the more or less Vancian magic of Terrae Vertebrae, this was the answer.
They might find a wealthy Patron, enter the officially mandated and recognised guilds, enter a religious order, become wandering ‘petty-mages’, wander in and out of naturally magical realms like Faerie, become hermits or try and form academic communities,
Wizards of a high enough level tend to be solitary creatures, who like to try and conduct their research in peace somewhere isolated. Even in the Universities, they lurk in their towers unless necessary/desirable to address a problem or cooperate on a shared project. They are detached from the world. A certain resemblance to the powerful, self-sufficient, self-satisfied creatures, of Jack Vance's Dying Earth would not be amiss.
As younger types, they raise money/garner good will by serving the powerful in some capacity....generally for something vaguely resembling/not entirely contrary to the greater good. We hope. They attempt to build up a reputation as a reasonable sort. Universities and Guilds enable Wizards to leverage power without being Clients of a Patron/Institution that might force something on them....but it can be very difficult to form a Guild, and joining one is likewise tricky. Guilds or Universities require high standards, either/both in one’s magical abilities or/and in ones probity. And an unprotected wizard might well have encountered problems with mob or the powerful of the world which can blot their copybook. Entrance fees are likewise high.
Adventuring wizards are something like Journeymen (whether attached to a Guild or Guild-like structure or no). They have mastered some basic spells, can speak and read Arcane or other Magical Tongues, and so are not Apprentices (who are presumably still mastering their irregular verbs). However, to be of a ‘Master’ level implies settlement, true accomplishment within the craft –to the point of crafting one’s own spells, as well as teaching others or in some way adding to the great body of magical lore. [Hence the proliferation of named higher level spells; Bigby’s Crushing Hand, &c. ]
Further, one imagines ‘Master Wizards’ are not so engaged in the ugly little pragmatisms of Adventuring, preferring to fathom the mysteries of the universe from their (possibly literal) ivory towers . Further, the use of a ‘Master Wizard’ on anything less potent than a dragon would be overkill; frightening to non-magical persons and authorities, demeaning to the master magus and otherwise unfitting. (Everyone remembers what happened when wizards tried to run things...)
Thus, our Player can never reach ‘Master’ level; this would imply they can pull thunderstorms out of their back pockets and peer through the aether to distant realms. Even if our wizards can stretch themselves at high enough levels to ‘Master’ level feats, I’m not letting them play with the fabric of space-time. Not that any of my players are have been anywhere near such a level. Player wizards cannot be Masters; it would require much more study than they have done. Decades more.
NB, any Master Wizards our Player Wizards may encounter may well be remarkably patronising about the Players quest and the line of work they find themselves in....