Mistwell
Crusty Old Meatwad
Hmmm...I can see the problem. The thing with unlimited cantrips is, if you take things to their logical conclusion, there is no reason why all the city's are not lighted by light spells and such.
Yes, there is. A mage can cast only one. That's it. As soon as they cast a second, the first one goes away. So you need one mage per light. Does that sound likely? It doesn't to me.
One thing with Dragonlance though is that, for much of the history of the setting, mages were few and viewed with suspicion and distrust, if not outright hostility. That might be enough to limit it right there.
We agree. No city will have the mages needed to keep the lights on.