He said the timeline would take place in the mid 50s.
By which point there aren't going to be many Pz.Kpfw. IVs left, outside of a few at the scrapyard or used as a bunker somewhere filled with concrete. By contrast, Shermans and T-34s were used by pretty much every European country up through at least the '50s, so they would be everywhere. Poland and Czechoslovakia were even making their own T-34/85s as well by that point.