Started there using their tube tester. Tube testers are gone, but the old vacuum tube sure isn't. That's about the only thing there I can say that about.
Actually, Radio Shack used to be Allied Radio. Here is a history:http://www.alliedcatalogs.com
I remember when it was Allied Radio, it had no physical stores, and everything was purchased by mail order. They had a lot of good electronic equipment including good audio systems (tuners, power amplifiers, pre amplifiers) and amateur radio equipment. One could buy amplifiers and tuners in kit form and solder all the components, i.e., capacitors, resistors, transformers, tube sockets, etc. onto the printed circuit boards and have good equipment at a much lower price than if it had come assembled.
Part of the downfall was the result of changing technology. Previously much of the cost of electronic equipment was in the labor of soldering all the components onto PC boards. Transistors and integrated circuits plus advanced automation made it possible to do all the soldering automatically thereby eliminating the labor cost of doing it manually. That eliminated the cost saving of buying in kit form. In addition, the quality of equipment available became mediocre. It's surprising that it lasted as long as it did.