Old-school D&D, to my understanding, has a significant "resource management" aspect to it - resting was more difficult, wandering monsters more common, and "resources" more rare.
In this context, I generally understand resources to mean spells, as that's typically what it means in a d20 context, the system I'm primarily familiar with.
I'm not talking about spells, though.
Item creation has generally been relegated to backgrounds or fluff skills, often with no real use past the first couple levels, if they're even useful then. So what if your 15th-level fighter is a blacksmith - unless he can make magical weapons and armor with that skill, it's worse than useless, as those skill points could have been spent in something useful like tumble or whatever.
I find this unfortunate.
I mean, what's one of the advantages of adventuring? Loads of money. Adventurers don't need day jobs, because adventuring is, effectively, a job. You find lots of money and loot, and you trade in that money for loot you want. Crafting requires spending money to buy "raw materials," and then the end product is something you probably won't use anyway because it sucks, and the return on investment is terrible comparable to adventuring.
But what if crafting were the means of money generation for an adventuring party? Or just resource management in general?
To the first question, no.
Adventuring is a money source. Crafting, which is time-consuming, becomes a hobby. Fred the Dwarf Fighter can craft armor well, but he only makes a mastercraft suit once per year, just to keep the edge on his skill. He won't even make it for WizMax his elf wizard "buddy" as crafting armor takes too long. WizMax could just buy it from a lesser craftsman who can put out armor of quality that is "good enough".
Of course, if your game has frequent breaks (eg adventures might be time-sensitive, but you only adventure every few months or years in-universe) then crafting has a place. But not really, since there's very little you can get out of mundane crafting other than feeling good. I don't think beating a DC 20 gives you anything good. (Eg if you can hit a Craft DC of 40, what does that give you? Nothing. Or at least nothing that's balanced.)
For the second, you need an entire subgame based around domain management, and that's actually harder than it looks. Not only is the economy not sensible (it's geared toward adventurers), but if the PCs start raking in the dough they want to spend that money on magic items and not on "business", making them OP and wrecking the scenario.
FATE and Mutants & Mastermind solved some of these issues, by making gear part of the character. (A FATE character has to spend an aspect/stunt on a piece of gear that makes them better. A sword costs nothing but money, but your grandfather's sword that you're so familiar with you get +1 to hit costs a stunt. A magic sword that also costs +1 to hit costs a stunt. I don't believe stunts stack, either.) Having said that, these are
not realistic games. Why does Captain America have to give up his cool bodysuit in order to get a better shield? Game rules. It's got nothing to do with realism.
I think both systems let you "save points" so you can whip up an invention when needed, but again, you're paying character power for that, not money.
Sure, this kind of moves away from the Conan-esque "kill things and take their stuff" sort of style. But honestly I find the idea of monsters sitting on huge piles of cash kind of weird anyway - I mean, once in awhile it could make sense, but all the time?
Gaming culture has evolved. Monsters actually use treasure, and dungeons now (usually) make sense. Goblins have gold because they've successfully raided the nearby community or merchant caravans. (If they
haven't been doing that, then the PCs are simply going on a boring slaughtering expedition.) Many D&D adventures feature humanoids with class levels (or, in 4e, the equivalent).
Doing away with cash-oriented adventuring also would help with the weird economics you run into in d20 (which was the fuel for my thinking about this sort of thing to begin with), and eliminates the crazy price inflation that happened with high-end items.
I ran into issues in non-D&D games where heroes didn't adventure for cash. It turns out they didn't want to adventure at all. Often they became money-grubbing, and would ignore any plot hook that didn't have an immediate cash reward.
Would anybody else like to see crafting be a more integral part of the game?
No. Leave it to the NPCs.