He had found substantial evidence not only that Americans were consuming fewer resources per capita but also that they were consuming less in total of some of the most important building blocks of an economy: things such as steel, copper, fertilizer, timber, and paper. Total annual U.S. consumption of all of these had been increasing rapidly prior to 1970. But since then, consumption had reached a peak and then declined.

The rolodex and the ice cream were just examples to ground the idea. I'm sure there's more to the story than spreadsheet-wielding MBAs, but I think it's reasonable to claim (and evidence can be provided for): 1) Spreadsheets have been used for two generations (VisiCalc, 1979) 2) MBAs are trained to optimize things like capital and labor costs, including the price and quantity of materials used in the products and services they manage.