Frugal YES, but why develop a garment that requires 8 yards of material? And all the accessories, sporrans arrn't cheap, sgian dubhs, dirks, balmorals, fly's, argylls, PC's...
Going back to your original question, one has to realize that the modern 8 yard kilt is, by and large, a garment designed for ceremonial wear. 200 plus years ago, when the kilt was still being worn as a work-a-day garment by many Gaelic Scots, it was a 4 yard garment -- only half the material required. And prior to the 1790s the kilt was not a truly tailored garment, either, so very little labor when into making it. And remember, too, that the cloth was not so dear at the time, either. All in all, the kilt, in its origins, is a very frugal garment.

Over the course of the nineteenth century one saw an increase in the amount of cloth used in the kilt, until we have the nominal 8 yard kilt by the end of the 1800s. During this same time, the kilt was being worn less and less for daily wear, and more and more only for special occasions. And when you have an article of clothing being reserved primarily for ceremonial use, you can expect some exaggeration and flare to be incorporated into the style -- the 8 yard kilt.

That's one reason why I'm such a fan of the 4 yard box pleated kilt, especially for those who are interested in wearing the kilt on a more regular basis than just formal dinners and Highland gatherings.

You also mention the high cost of many accessories. Much of what you mentioned belongs to the realm of formal wear. And formal clothing is going to be more pricey than the casual stuff, no matter how you slice it. But unless you attend a lot of black tie affairs, do you really need to buy your own Prince Charlie jacket, or Montrose doublet, or formal sporran, etc? How many men today own their own tux?

All that is really required to wear with the kilt is a good pair of kilt hose, garters, and a sensible sporran for day wear. Every thing else is just gravy that you can add as your budget allows. (Makes Christmas and birthday shopping easy for your loved ones, too!).

Aye,
Matt