@CWO-Marc As for what we did and did not have back in 2000, I made a small chart
Unit from Classic (1984)
Aircraft Carrier
Anti-Aircraft Artillery
Battleship
Bomber
Fighter
Industrial Complex
Infantry
Submarine
Tank
Transport
Units Added in Europe / Pacific / Revised (1999/2000)
Artillery
Destroyer
Units Added in Anniversary (2008)
Cruiser
Units Added in Europe 1940 / Pacific 1940 (2009)
Mechanized Infantry
Tactical Bomber
Units Radically Changed in Europe 1940 / Pacific 1940 (2009)
Industrial Complex
Units Radically Changed in the Second Edition games (2012)
Anti-Aircraft Artillery
Units Added in Zombies (2018)
Zombies
So, yes, both a lot already around in 2000 and a lot more still to come.
-Midnight_Reaper