So either I'm in denial or you're being too hard on yourself!
[ though all bets are off if you were at PARC when they were lighting it up, in that case... you definitely are old :) ]
My first week was, after getting in from school, going around to people's offices and swapping whatever network card was in their machine for a 3C509 combo card that had base-T, base-2 and another port that I think was AUI if I remember right. That way the transition would be easier when the new office was ready.
At the end we had a bunch left over and my boss let me keep them. That was my first NIC. I think I still have it somewhere. I gave some away to my friends so we could have LAN parties. :)
Never had to deal with token ring though, just TCP/IP and IPX/SPX.
So not quite in the PARC realm, but not too far from it.
I have done this multiple times and was really happy when we finally got RJ45 cables.
Less of a problem once the coax was retired as there is no direct electrical connection between the computers.