Game play around D&D revolves around adventuring, ergo it follows the purpose of magic is primarily to support the main activity players are engaging in. This is the primary reason why most settings haven't put a lot of thought into the long term ramifications of certain spells. It doesn't matter because we're here to adventure not worry about nerd stuff like the economy.
This is the usual explanation, but I really find it quite unsatisfying. It makes the PCs separate from the world they presumably were born into and grew up in, because the rules only care about them. I don't want to play in a world where only the PCs matter, and I really don't want to run such a world.
Shadowrun, at least 5th edition, is similar. One of the books, the main book I think, makes it a point to say that consumer magic is available and used for all sorts of purposes that just aren't covered by the rules because it doesn't have anything to do with the principle activities expected of players, which is running. There are some practical reasons for this with the number one being you can only put so many rules into the game. You only have so much time to write the book and so many pages you can devote to any particular subject.
At least Shadowrun acknowledged that magic outside 'running exists. D&D usually doesn't bother.
Over the years there have been many different settings for D&D. We've got Forgotten Realms, Greyhawk, Dark Sun, Ravenloft, Birthright, Conan & Red Sonja, Dragonlance, Lankhmar, Red Steel, Planescape, Rokugan, and there are many more I can't even remember. Shadowrun has the advantage of only have a singular setting.
But the vast majority of those settings (Eberron is a clear exception) do not acknowledge the presence of magic in a non adventurer-centric form in any real way. And let's be honest: they've had a long time to put some work into it. Those few times I seen ink spilled on the subject are greatly appreciated.
I don't allow rerolls. the party gets one shot at the thing. They decide who does it and who supports and who might want to spend spells, but they get one roll and deal with the consequences of that roll.
I don't think that is true, at least for the Realms and the Known World (BECMI). Both of those settings had at least one, and in the case of the FR more, books full of magic aimed at things other than adventuring.
I'd love to hear about them.
Aurora's Whole Realms Catalogue has adventuring magic, but also much more.
