I suggest that "High End" is a design and manufacturing philosophy, more than any particular piece of electronics. Back in the 1930s Stromberg Carlson, among others, built console radio/phonographs that were sonicly greatly superior to most, cosmetically styled, made with the finest workmanship, and, of course, priced accordingly.
The Single Piece That Started Today's HIGH END ?
I have no idea myself but it has been suggested that it may have begun in the mids 1970s, with a Mark Levinson preamp. It apparently cost more than anything anybody ever concieved a piece audio gear could cost before. It may have simply been here since the start of McIntosh (1949) which was always a more expensive and exclusive brand. What are your thoughts?