I think the point is, your settlers are poor schmucks. Why get things that are 3x as 'aluable for the same price? (Your starting points are ☼, after all)- and complaints about "unskilled" making the good stuff- well, they DON'T.
So for 90☼ I can get 30 logs, which I can turn into 29 barrels (not -barrels- even) or I can spend that 90☼ on 9 empty barrels.
Would you rather have 29 barrels or 9?
Would you rather wait for X dwarf-days for them to be constructed (and, as you note, ha'e a startup-cost for workshop), or not? You turn dwarf/playtime into money. For normal dwarfs, time in'ol'es a bit of food and drink upkeep, a nonob'ious element of time cost- other things include nebulous "protection from critters", and whate'ers needed to keep them sane.
At least in the case of weaponry/picks, the timecost of making better things can become important enough that trying to make your party weaponry will crumble your fort when bringing the weapons pre-constructed would ha'e sa'ed them, particularly if you're trying to turn {2 logs, 5 bit. coal, 4 limestone, 4 hematite} into {2 steel axes, 2 steel picks} of quality.
Analogously: You ha'e 7 dwarfs. You can turn them into arbitrarily many dwarfs with time(barring single-sex embark parties, using more food and drink gi'en the large amount of dwarf-time required). Should you be able to take arbitrarily many dwarfs along on embark for free(since the first 7 are free, why not more?) therefore?
You can bring along seeds on embark. You can turn these into arbitrarily many seeds and plants gi'en time (and some non-freezing soil, and again dwarftime). Should you be able to take 200 seeds for 1☼? And X plump helmets/quarry bushes/etc?
If you embark with an an'il, three iron ore, four charcoal, and a stone for the workshop (only a starting cost), you can make another an'il. Should an'ils cost 1115☼(1000+24*3+10*4+3)? Or 112☼ since you can make an'ils beyond that without making more forges? Or 87☼/84☼ since you can just make a wood-furnace, burn wood to charcoal, deconstruct and then make your forge? This in'ol'ed case of making an an'il is rather demonstrati'e of how you get to pay less and less for more and more dwarf-time in'ol'ed.
To far absurdity: You bring along an expeditionary force composed of 7 dwarfs and some goods to a landscape. Gi'en time (and without spending a single ☼ in buying things, just dwarf-time, once you ha'e a pick, an'il and axe you can in theory do anything map-possible with enough time), you can turn this into a large fortress, megaconstructions, which is a Mountainhome. Should you be able to take megaconstructions or the King with you on embark for free, as you seem to be indicating that results of dwarf-time/playtime should not cost anything more in ☼ than their components at embark?
Why should results of dwarf-time and skill cost nothing more than without?(Other notes: And depending on 'ariety of cheap meats and whatnot, I can get up to 45 barrels with food for 90☼ without spending dwarftime. I hear this is on the "to-fix" list. Perhaps additionally making it that you need to buy another wagon once you hit the 15000Г limit?)
As for crafting failures, these're dwarfs. "The craftmanship of the dwarfs is unparalleled," as humans say. Perhaps rising material-efficiency with skill (Unskilled dabblers take a lot more wood to make item A because they don't know what's essential, and legendaries take a lot less because they know that what those of medium skill consider essential is not) would be possible, but that's a suggestion that I do not care for and isn't the one of this thread.
edit:Any merchant knows [ETHIC:TRADING_AT_A_LOSS:UNTHINKABLE]./edit
For those who say tl;dr: shame upon you and a pox upon your brain for saying such a thing.