Fisher products pre-1969, when Avery Fisher still owned the company, were well-built, higher priced products for their time, but reflected Fisher's own listening preferences (warm voicing that favors classical music). Most products built during this period were built to this same sort of builder-preference model, so when you went out to compare products by Fisher, Scott, Pilot, Sherwood, Harman/Kardon, AR, JBL, etc., there were definite differences and you picked what suited your own personal taste.
Fisher products made after Fisher sold the company reflect the "mass market" goals of the company's buyer, Emerson Electric (later followed by Sanyo), whose consumer products at the time mainly consisted of table radios and TVs of lower quality and price points than Fisher's. So in one fell swoop, the company's products lost both their sonic personality and their reputation for high quality. A similar fate befell many of Fisher's competitors, who today tend to exist either in the same way Fisher does (as brand names for low-end products that tend to look and sound alike) or not at all. Only a very small number have managed to preserve some prestige for their brand names, usually by spinning off higher-end variants.