I've been enjoying all the responses to the 1983 / 20-year cut-off date question. Especially since I'm being reminded of different events and learning about others.
Being the owner of three Japanese bikes--an '83 Fuji, an '84 Schwinn (National), and a '92 Bridgestone--I guess my viewpoint isn't quite Campy-centric.
Someone mentioned SunTour's demise in a post. For me, I think that was the end of an era. So long as well-made, lugged steel frames were being fitted with SunTour Superbe Pro components (and Cyclone and Sprint, for that matter), things were good. When SunTour went down and their friction derailleurs disappeared from the marketplace, the dark days had taken hold.
That said . . . I know the new stuff works. On my Bridgestone RB-2, with Shimano Ultegra bar-end shifters I specified, I could switch between SIS and friction. Though I pretty much stayed with friction, I did try the SIS and it worked fine. I imagine all the better Shimano derailleurs--Ultegra, DuraAce--worked even better than my mid-range unit, and that the new Campy stuff is great, too.
Still . . . I eventually replaced the Shimano derailleurs with SunTour Cyclones, and the Ultegra shifters with SunTour BarCons. And thanks to Jim Narlesky's discovery of 3UB axles in a California shop local to him, I was able to install a Sugino AT crankset, too.
Anyway, I don't have any real suggestions regarding the time-frame of the CR list. Fine steel frames are still being made, and that's good. 531's gone, and that's not good. There are all sorts of criteria that can be used to figure out when the "classic" era ended.
It's just my own personal time-frame for the end of an era coincides not with anything Campagnolo, but rather with with SunTour--its innovations, its quality, and sadly, its demise. My '84 Schwinn Peleton, thankfully, is a lugged Columbus frame decked out with Superbe Pro hubs and derailleurs, DiaCompe NGC400s brakes, a Sugino Aero Mighty, downtube shifters, and for that I'm glad.
Nath Dresser
Spring Green, WI