15gp officially is 150sp is 75 days of unskilled labor. A smith is skilled so he takes 2-5 times of that and needs one day for the sword so plus material and profit your sword comes to realistic 15sp and that's the way I do it in my campaign.
it is not about the absolute numbers what makes the phb prices so unrealistic it's about the relation.
Still the relation does not fit, how do you fail to see this?
If we take the standard high middle ages setting as a base then 1gp is about 100 $ compared to our time in what it can buy. People sometimes where in the plight to buy themselves a weapon to serve as an emergency militia.
Let us take a battle axe, although somewhat more expensive than a woodcutter axe its make is quite similar.
It is 10g as per PHB equivalent of 1000 $
Let us asume a woodcutters axe costs half of it then it would be 500$. Back then it was handcrafted, but labor was much cheaper, so it is comparable with todays price which would be some 20 - 30 $ at the toolstore most. And today you got all intermediate sellers taking their share etc.
No one could afford a weapon if the PHB prices were real! They could not even afford a tool!
20 arrows 1gp! Are they mad???
But the solution is totally simple just make it silver for all the weapons and armor instead of gold and everything fits together once more.
A maul 10gp = 1000$! That is a simple tool, english longbowmen took these along to build their tents and its second use was to crack open the plate armor of a downed mounted knight.
Every archer would be like "oh i grab the big hammer, desert, sell it of and then i am a rich man for the next months"
Edit here is a cite from myarmoury.com/talk/viewtopic.25025.html by a James Barker:
15th C England basically went like this:
You had "li, s, d" or "pounds, shillings, and pence". 12 pence in a shilling and 20 shillings, or 240 pence, in a pound.
Average sword was a pound.
Average person made 2 pence a day; so 120 days of labor for a sword.
Skilled Labor could make 4-6d a day, someone like a stone mason.
Archers made 6d a day on campaign so 40 days of campaigning for a sword.
Helmet cost about the same.
a pound is 20 shilling = 20 silver =1g (historical), so a sword was 1g which is far nearer to my 15s than your and PHBs 15g
The average labor is even cheaper, but skilled labour is about 2-3x what phb states for unskilled so my guess was also good here.
Okay, I'm going to start by looking at money as time, not at actual "is this gold or silver"
According to your numbers, the unskilled laborer in the PHB needs 75 days of work to afford a sword.
According to your historical numbers, an unskilled laborer in England 15th C needed 120 days of work to afford a sword.
If we take the Blacksmith as a skilled laborer in the PHB, they need about a week to afford a sword.
Looking at your historical numbers, the Blacksmith making the high end of 6 pence would need about 40 days.
Soldiers are actually in between this, implied to only earn a single gold a day
So, what does this tell us? It tells us that the skilled laborer is making far more than the unskilled. By a wide margin.
But, there are a few extra factors here.
1) There are no degrees of skill when it comes to tool proficiency being calculated here. The master goldsmith for the emperor is accounted in the same way as the village man who taught himself to fix the plows.
2) Skilled labor covers all proficiencies. It covers the smith and cobbler the same way it covers the jeweler and diplomat. All are "skilled" so they earn more money.
3) The wages were directly calculated in the PHB out of room, food, and drink. A "skilled" individual is supposed to be affording nicer clothes, a house and associating with merchants and other tradesmen. Buying a comfortable meal, a comfortable inn, and a mug of ale is a total of 13.4 silver, almost the full 20 silver they are making. Meanwhile, "unskilled" are supposed to be at poor lifestyles, having threadbare clothing, living in a flophouse room, and without a stable community. For poor meal, poor lodging, and a mug of ale, it costs exactly 2 silver. This is actually a problem, since it means that all of their wages are going to keeping themselves above water.
4) We have to remember guilds as well. Most skilled workers are likely part of a guild, and the Guild Member background tells us that guild fees are 5 gold a month. So, skilled craftsmen also have to be able to afford that additional cost, as well as any training fees and fees for their tools and work area.
5) Scaling is different when you have 1 -> 20 -> 240 for historical money and 1-> 10-> 100 for DnD money. A single gold is actually worth less than a pound in this system, in terms of ratios. A Pound is 240 of the smallest unit, while a gold is only a mere 100. That means in terms of buying power, you would need to divide all the gold prices by about 2.4 to get an accurate ratio. Which changes everything else I talked about up above.
I will agree that some of the weapons are priced oddly for what they would have been in RL. A maul as we picture it was a siege weapon meant for bringing down doors, and was just a think log of wood bolted with iron. Most DnD mauls though, are giant slabs of steel, which changes the pricing drastically. I'd say a traditional wooden maul would be closer to a greatclub, which is only 2 sp.
And, I think that is a final point of consideration. Most of the weapons that are made of metal, are assumed to be military grade and made of steel. A poor hunter isn't using arrows that cost 5 copper a shot, those arrows have steel heads and were made by a professional bowyer. They are using the arrows they made, possibly with iron heads or stone heads. Which cost a lot less, but the game doesn't cover all of that. The game is vague and only cares about what affects the players.