It's my observation that these so-called "scrappy" quilts are the product of people who have excess money to spend so buy yardage as if it grew on trees and/or lack the math skills to precisely calculate the need for a given design, and either overbuy or underbuy to such an extent that they have unpredictable quantities of fabric.
In my youth, the scrap bag truly was the scraps -- well worn odd bits which were used again to create functional but not artistic homegoods. Every inch of a new bolt was conserved and when we cut, it was with a thought to the most economical method possible.
I do find some of the new "scrap" quilts visually pleasing, though I can't imagine the waste!