I feel like this mentality is part of what is wrong with LotC. Magic shouldn't have to be spread super far. If people don't want to take a student they shouldn't have to. Its why I argued for the lore change to Paladinism, to remove the TA requirements to progress from t4 to t5. You just add a lot of bloat in the player base by forcing the magic to grow in players.
Though, I'm not saying people should pull a dragonroost and write magics to make their characters more powerful, but making it so you have to have x people with a TA after y months isn't it imo.