This isn't entirely fair and is actually pretty flippant and tone-deaf given the situation of the time after the war.
In 1948 the US had been industrialized for much longer than the USSR. It was a destination for immigration, and had a vibrant young population. The two world wars it participated in were fought on foreign soil, far away from the homeland. After (and even during) WWII it benefited from a massive influx of European scientists and intellectuals. Industrial capacity from the war was redirected back to consumer goods.
The Soviet Union on the other hand bore the brunt of losses in WWII. It suffered massive deaths in the war, especially among its young men of working age. It was invaded by NAZI Germany, and some of its largest cities occupied or put under siege. Its agricultural and industrial lands were ravaged by war, its people by wartime famine.
While the Soviet planning system was a failure, and Stalin an evil tyrant -- in 1948 a working class person in the USSR not being able to afford a car had very little to do with the different economic models, but with the completely different situation of the two countries.
(Even if the movie/book was set in the 30s, the context it was being look at was post-war USSR. And even in the context of the 30s, the USSR had only just come out of civil war, revolution, and WWI)