Maybe the USSR never had intentions to conquer territory.
35 years ago, in my first professional employment, a guy insisted that 'the Russians' would march in and take over 'in our lifetime'. They never even made moves in that direction.
Think about it: North America is huge. Taking it by force, then holding it, is a strategic and logistical nightmare. You especially wouldn't want to try it through a tiny bottleneck like the Bering Strait. Then think about administering it...
The Soviets always preferred subversion to conquering, anyway. Only twice that I know of did they mobilize major elements of their armed forces for forays outside their borders: Hungary in 1956, and Czechoslovakia in 1968.