Starbucks was founded in 1971 and went nationwide in 1986. Pretty sure most businesses adapt their business model in response to the market over the course of 50 years. Especially when you consider the difference in commercial rent in 1970’s Seattle to today’s Washington DC, you can see how a low-margin establishment with a low per-head spend cannot survive without high customer turnover. Customers camping out all day isn’t conducive to high turnover.
I can put that in PowerPoint if that helps :)