The first space station was created in less than year and a half.
This statement is both technically true and also misleading. The hardware used there was worked on since 1967, on the conceptual stage. And the original ideas were discussed even earlier, in 1960s. However, the principal decision to actually go ahead with the project - with all associated resource allocations - was made in the Soviet Union higher levels of leadership somewhere around November 1969, while the station, Salyut-1, was launched in April 1971, and was successful enough to have two crews launched to it, one of which even made 23 day long program of activities onboard.
How come the orbital space station, something which didn't exist before other than in a form of studies, leaped into reality so fast while working even on the first try? Particularly interesting is that it was made by the Soviet Union space industry, which was focused on their manned Moon program at the time - the project which ultimately didn't lead to human flights outside of low Earth orbits. That industry inaugurated an important sector of human spaceflight seemingly as something trivial.
There are reasons how it could happen. There are enough people involved, stories told and documents available which paint the complex picture - for example, the story of successful onboard mission is completely shadowed by the death of the crew on the way back to Earth, and the time to orbit for Salyut-1 was greatly improved by using an existing station hull already made for Almaz. But for one of the reasons it could be said that, actually, a simple space station is not that hard to make. The idea is similar to modern industrial phrase - "the rocket science isn't a rocket science", which means that these days we're much more comfortable with technologies which in 1950s and around that were considered the pinnacle of technical achievement. We can look into more details what constitutes the space station and make a better picture of what's needed - and how it could be done.