I agree to an extent. Forcibly breaking up Germany wasn't feasible after either World War
It happened all the same. Even if you disregard East and West Germany, the lands lost elsewhere which weren't previously annexed by the Nazis were quite significant. Some of the areas which were annexed by the Nazis would likely have voted for annexation at the time (Austria), and they were broken off, too.
With both Germany and Russia I am referring to the "core" nation, not peripheral bits.
Yes there was the division of the former from around 1950-90, but that was a product of the Cold War - it was not the original intention of the Allies come the end of WW2.