Well, it looks as if I will be the only one with hesitations about this craftsman/mechanical division. I've seen brass items, wood work, jewellery, rugs that have been hand made in these modern times and I wouldn't say that all of them were so special. Some yes. But I've seen faults and weaknesses that the modern craftsman has just shrugged off or was too harried and hurried to fix, possibly because he had a quota to meet. Or joints where too much material was blobbed together. At the same time, I've seen hand made modern quilts that are every bit as meticulous and beautiful as historical quilts, but these quilts were not made to be marketed.
Much depends on how 'quality control' is applied. With mechanical construction, that is determined by economics (cost), quality of tooling and machining, and the expected cost that the item will fetch. That is, who the item is being constructed for. A Ford has a rather different construction than, say, a Jaquar or Lambergini. (And some even say that the day a car is constructed has a bearing on the quality of its workmanship.)
I think those same economic factors applied as much in the past. Some smiths might work fast to put more items through to get more bread on the table. Some smiths might take a shine to a particular customer (possibly the wealthier ones but not necessarily only those of deep pockets) and do special work for him or her. Some smiths might work on an object out of pure interest or love--if they had the time and financial freedom to do so. But always, the economic situation would impinge upon the craftsmanship.
I've also heard that some of the Queen's carriages are a tad uncomfortable to ride in as their suspension system or springs and shock absorbers are not as accomplished an art as those of modern, horseless carriages. But I think
Morth has suggested this point earlier.
So, its economics + labourers' attention + technical knowledge if we are using objective measures of worth. If we argue that worth lies in the eye of the beholder, though, just as meaning lies in the reader's mind, (
) then that's a subjective measure where some prefer enchantment or others advancement.