How do you define 'today's high end'. If your definition is based on the beginning of major emphasis on 3D imaging then I would have to nominate the ARC SP10II in the early 80's and the CJ Primere 3 as well although sonically it was not as balanced (neutral) as the SP10II.
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?