Especially Germany. Were they just outdated by the time the occupational forces handed over control to the new governments?
It was -
In terms of armour, the French used Panther tanks until about 1950 while Stug III's and Pz IV's saw service with the Syrian army until the early 1960's.
In terms of aircraft, the Swiss, Finns and Romanians continued to use Bf109's into the 1950's
The Bundeswehr, the modern German army, was founded in late 1955, by which time all of the ex-Wehrmacht material had become comprehensively obsolete and out of production.
The Panther - even in its heyday a mixed bag of good and bad design features - had long since been eclipsed by the MBT's and every German aircraft type of WWII vintage had been thoroughly outclassed by the second generation of jet aircraft.