As a listmember for the last 5 years or so we have had this discussion of cutoff date at least twice a year, though this time its gone on with more than a few emails from the Chief. Campagnolo tended to build the same stuff forever (pre1983 cutoff) while Shimano tried to reinvent the wheel on a weekly basis Eagle followed by Eagle II etc............500,600 ,Titlist, Tourney (2 or 3 times),EX,AX , FF(at least twice)and lots more now faded away. We would spec out a bike with one type of derailleur and 6 months later see it replaced by something else.Even maintaining a small inventory of replacement parts was a major job. I look back and appreciate the simplicity of the old style derailleur systems and the fact they were repairable. Today it seems like the answer to every problem is throw it away and get a new one, but you can't do just that you need to "upgrade"as your 2 year old stuff is way obsolete. Over the weekend I had a chance to ride a bike with a 1st gen DA group and it worked just fine.
old school all the way in MILL VALLEY ,CA USA