That’s because each nation during WWII learned different lessons during that war. USSR build their tanks to be cheap because they know they will lose equipment and men. They accept that losing soldiers is going to happen so they tend to use numbers to gain the edge, however they haven’t needed to do this since WWII. The last tried this in Afgan and it didn’t work so well.
The US can’t take loses for $hit, so we try to destroy you from the air, far way, as fast as possible and units that are designed to be in your face while fighting are armored up.