The USSR had won many firsts in terms of human space travel, but why/how were they out performing the USA and other world powers at developing the appropriate technologies required for their landmark achievements in space? Was it an element of their culture, a capability of their socialized economy, or something else?
The USSR's initial advantage in the Space Race was because it invested in rockets in a major way after WWII, because it wanted missiles to hit the USA from the other side of the globe. They put essentially all of their work into the rocket basket, starting as early as 1949.
Now the follow-up question is: why didn't the USA do the same thing? The US did not start seriously investing in heavy rocket production until 1953, after it had successfully tested the hydrogen bomb which would make such things worthwhile (H-bombs give you enough explosive power to compensate for lack of accuracy). Prior to that, and even during the 1950s, the US invested almost exclusively in long-range heavy bombers, which is how it dropped its atomic and conventional bombs during World War II (which meant it had a lot of experience with them, and the USAF hierarchy was full of bomber-engineers), and suited its geopolitical situation well (the US had allies, and shared bases, close to the USSR's borders, and from there could launch devastating bomber attacks, whereas until the Cuban revolution, the USSR had nothing near the USA's borders).
Which is to say, the USSR wasn't "so proficient in space travel." They just invested a huge amount of technical infrastructure into it for a longer amount of time than the US did. Why was the US less proficient? Because they had gotten a late start on rockets, because they spent most of their time worrying about bombers. If the USA had started investing in long-range rockets in a big way in 1949, would they have developed one capable of putting a satellite into space by 1957? I mean, it seems kind of impossible to conclude otherwise: as it was, the schedules were very tight (the USSR had a very slight lead — the USA put a satellite into orbit in early 1958).
The USSR was also, it should just be noted, willing to rush things out the door a bit early to capitalize on propaganda value, and while their launch schedules were secret, the Americans' largely were not (the US rocket program, even though it contained much secrecy on the technical level, was very much a public phenomena). So there were information asymmetries there — the USSR could plan to "upstage" the Americans, the Americans had a harder time doing that in reverse.
What made Sputnik a "shock" was not so much that the USSR was light years ahead of the USA (it was not, it was maybe half a year "ahead"), but because there had been an idea, prevalent at both low and high ends of the US social hierarchy, that the US was light years ahead of the USSR in every relevant technology. By hyper-focusing on one technology, rockets, the USSR managed to "catch up" and, in a small way, "surpass" the USA for a brief moment. That was big news to anyone who thought the USA had a comfortable technological "lead." It also meant that, within a few years, the USSR actually could strike American cities with nuclear weapons, which had previously been a much more chancy endeavor.
But the distance of that lead should not be exaggerated. The USA still had overwhelming superiority in many areas, notably long-range bombers, and quickly surpassed the USSR in rocket and space achievements as well. Here is a slide I use for teaching to illustrate the differences in strategic choices made by the USA and USSR — you can see that the USSR did have a teeny tiny advantage in missiles in 1958-1959. But that is against the backdrop of overwhelming US advantage in strategic bombers, and then a rapidly exponential US missile growth. The USSR's production system lagged behind the US one by about 3-5 years, despite their early successes.
On the USA's choices regarding missiles vs. bombers, I have written a bit on this here, with lots of references. As for the Soviet rocket program, the work of Slava Gerovitch and Asif Siddiqi is great and informative.
As a follow up: since most of the relevant German engineers in WW2 were "hosted" by the US and the Soviet Union, is it know about the benefits they had and the way they were treated in the two different countries?
Related question - US and Soviets were obviously the two main space race players. Was anyone in 3rd place in the 'race'? When did a third major space player join the scene?