The short answer is that making shoes is a business. And when you start talking about factories, job one is profit maximization and a lot of that comes down to cost control. If they don't need to use high quality materials, it doesn't make economic sense to do so. Now for the long answer... The original Goodyear machines did try to come close to handwelted quality. Handwelted relies on very good quality vegetable tanned leather for insoles and of sufficient thickness that a channel can be cut into the substance of the insole to create a "holdfast"--essentially a ridge through which the awl is driven and on which the stitches are tightened. So, to begin with, the the original machines used essentially the same quality insoles as Traditional handwelted bespoke makers were using. Two opposing angled cuts..."channels"...were made, by another machine, and the leather turned 90 degrees to the natural "lie" of the fiber mat. These two "flaps" of leather were cemented to each other to create a facsimile holdfast. But bending the leather like this put a severe strain on the fibers and, additionally, the channels had to be cut so close to each other that the result was often pretty weak. The solution was to reinforce the leather holdfast with canvas or linen. Eventually it was decided that the linen all by itself could hold the stitches almost as well as the linen and leather together. So the machines were redesigned to utilize a linen holdfast known as "gemming." The gemming was manufactured in rolls that could be applied by another machine which positioned and cemented the gemming to the fleshside surface of the insole simultaneously. About this time it became obvious that a really high quality insole leather was no longer needed...the cement would adhere the gemming to a mediocre insole just as well as to a quality insole. And at the same time, since a channel was not being cut into the insole, a thinner insole could also be used. All of this saved the factories money. Lots of money--both in terms of eliminating jobs that required skilled shoemakers and in terms of the cost of materials. And once the shift to Goodyear construction was made the degradation of materials and techniques became inevitable. AFAIK no company that began life as a high quality handwelted shoemaking firm and subsequently shifted to Goodyear techniques has ever reverted to past procedures or materials. Today, leatherboard and fiberboard---both composites on the order of particleboard or cardboard--are routinely substituted for components that were traditionally made of leather on the highest quality shoes, ie., leather insoles, heel stiffeners and toe stiffeners, and heel stacks. Finally, it is my opinion...and it is an opinion...that the difference between a $100.00 shoe and a $500.00 shoe is insignificant. In all likelihood the materials used are not substantially better or worse and the techniques of manufacture are for all intents and purposes, identical. Above $500.00, it is a crap shoot. And above $1000.00 per pair the biggest drawback is probably the Goodyear technique itself. Because when you come right down to it, the basic principle holding the shoe together is adhesive--it is cement construction, for all the misleading hype. .