Looks like Radio Shack was started to sell equipement to hams. 

The company was started as Radio Shack in 1921 by two brothers, Theodore and Milton Deutschmann, who wanted to provide equipment for the nascent field of amateur radio (also known as ham radio)

Click on the link below for more informaiton on the history of the company.

RadioShack 1921

https://en.wikipedia.org/wiki/RadioShack#The_first_40_years