Ploughman your correct, Epiphone was a stellar guitar brand until Gibson ownership,
I am pretty sure that Epiphone truly hit the skids in the 50's. In 1951 their union went on strike shutting down production for several months. In 1953 they moved the factory to Pennsylvania. Left behind were many of their craftsmen. Curiously Guild Guitar company came into being (in New York) in that same period.
By 1957 when Epiphone sold itself to Gibson, for $20,000, the disastrous move to Pennsylvania had dragged the name into the dirt. Gibson can wear some blame thereafter, but the initial decline of Epiphone was on the family's (Stathopoulo) watch.
It's a similar parable to the perilous peregrinations of Gretsch, where they eventually wound up with a factory in Booneville, Ark. but no skilled labor.