The Last Slide-Rule Manufacturer.
If you want to look at the downsides and limits of “market category thinking,” the slide rule category provides some excellent examples. Keuffel & Esser Corporation, a company founded in 1867 in Manhattan is a good place to start. In 1962, the company introduced it’s DECILON slide rule into the booming market for slide rules, and on the strength of this line was able to go public on NASDAQ in 1965. But by 1982, the firm was forced to declare chapter 11 bankruptcy. This same year, AZON corp buys ownership of K&E Trademarks and K&E is no more. 
ARISTO had over a century of slide rule production, but was forced to close in 1978. 
Sphere Research Corporation of British Columbia, Canada, runs a web page devoted to fans and collectors of slide rulers.
“In these company archives, you can find very detailed info about the rules and models they made, the company and its history. Some rule makers were in business almost 100 years, and their histories and products are fascinating. Some major makers still survive today, but without any help from slide rules, as their businesses are now quite different. In the 1960’s, the industry was at its most sophisticated, and there were large slide rule manufacturers all over the world, each with their unique styles and features. This industry and technology survives today mainly in the form of slide charts, and the hearts of collectors.”