Non-adventuring Magic?

[BiggusGeekus]

Just keep in mind that some of these spells have costs. If I remember correctly Continual Flame costs 50gp of ruby dust to cast. There's no way even a sizeable farming town is going to get their hands on that (at least without a markup). You'd probably see a rather large division of wealth between the "haves" and the "have nots" that would be greater than in a technological society.

Or not. Who knows?

Incidentally, going to the city and rounding up 50gp of ruby dust would be an excellent adventure for 1st level characters. A few bandits, a mugging, a swindler who tries to sell the party red sand. You'd be able to work out a few softball encounters that are ideal when the wizard only has three hit points and the fighter isn't that much better of a combattant than the cleric.

 

[Steverooo]

The problem is money. With enough cash, you can do any of this.

A new spell to clean city streets, or dispose of sewage.

The Clean Cantrip can do this (now part of Prestidigitation?)

Spells that do such things as plowing, gardening, painting entire houses, etc.

A P;ough of Telekinesis will do the first (but be too expensive for anyone to afford!), and I believe the Color Cantrip would do the second.

Spells that play music, either with or without instruments, for bar/inn patrons and diners.

Already covered, above.

Items that let you use Cantrips, at will, would still be fairly cheap. As the spell level increases, the rarity of the item will, also.

 

[Monster Manuel]

My world, Morningstar, takes a lot of these things into account. Money is the greatest concern, as I see it, but with the coffers of an empire, and far-sighted leadership, implementing everyday magics are more cost effective than than the mundane alternatives over the long run. Morningstar doesn't explcitly use the continual flame lamp idea, but here's how it might break down, cost wise.

Assuming an average of 10 hours of full darkness per night, that would be ten torches a night, or 1.6 flasks of oil. Cost per night is 1 sp a night for torchlight or 1 sp and 6 cp for oil lamps.
torches cost 36 gp and 5 sp per year. Oil costs 58 gp and 4 sp per year. So even after 1 year, for oil, the cost is made up by the spell, assuming the person who cast the spell didn't charge for the act of doing so. Over many years, the saving continue to grow.

I agree that the initial costs would be too high for a small town or village, but any forward looking large town or city would likely use such a solution. If they put any thought into budgets at all, there's a decent chance that they will implement a policy of continual flame lighting, barring red tape that prevents logic from prevailing.

The primary consideration, though, is whether you consider this kind of 'realism' fun. All the cost/benefit analysis in the world can't overcome that requirement.

(edit; typos)