The Rise and Fall of American Growth: The U.S. Standard of Living since the Civil War (The Princeton Economic History of the Western World Book 70)

by Robert J. Gordon

However, just because new forms of food merchandizing were being developed does not imply that all working-class shoppers flocked to them;

It kinda does. The fact that 15,000 locations opened in a few years and the companies operating them became huge implies that a lot of people were flocking to them...