How Fantastical Do You Like Your Fantasy World?

[aramis erak]

It wasn't ever (to my recollection) stated outright, but the inference I got from TSR-era A/D&D was that answer to all questions about the fantastical reshaping the gameworld were answered significantly by rarity. Magical light did not replace torches and lamps because magic users were rare, took a lot of training, and didn't get better at magic use by casting continual light everywhere the local movers&shakers would want them to.

Actually, in AD&D and BX, they could get better by casting continual light everywhere... provided they were paid to do so. Each GP was 1 XP.

 

[Willie the Duck]

Actually, in AD&D and BX, they could get better by casting continual light everywhere... provided they were paid to do so. Each GP was 1 XP.

Potentially. Both*,** only state (although especially with AD&D** I'm sure this is contradicted somewhere else) that treasure taken while on adventures has the gp=xp rule apply to it. Regardless, I meant in terms of broad strokes, not ackchyually-proof purity. Travelling all over a barony or kingdom to cast continual light in three rooms of this castle, then in two spots in an important temple, then illuminate a strategic mine is going to net you some gp (and xp, DM permitting), but not like going and being an adventurer would. That's the primary point -- in TSR-era A/D&D, characters with economy-disrupting/world-remaking powers were both rare and off being adventurers. At least until name level -- then they might sequester themselves in towers and make magic items (IIRC this explicitly does grant some xp), or if you prefer they could go on an international tour magically illuminating places***, but that level is rare enough that it doesn't completely re-shape the world.
*Per B22: "When the adventure is over, the DM gives experience points to the surviving characters. Experience points (abbreviated XP, as ep stands for electrum pieces) are given for non-magical treasure and for defeating monsters. For every 1 gp value of non-magical treasure the characters recover, the DM should five 1 XP to the party (this will be divided among all the player characters)."
**Per AD&D DMG p. 85: "Treasure must be physically taken out of the dungeon or lair and turned into a transportable medium or stored in the player's stronghold to be counted for experience points."
***perhaps that's how all those pre-lit places in various dungeons got that way.