We see that during 1970s, especially the first half of the decade, both space superpowers launched space stations and crews to them, learning docking, EVAs, scientific work onboard, the technology of the stations. The concept was simple - the large place safe to live in, the transport spaceship, the docking, the resources available. Those were the first "homes in space", allowing to switch from the "transitory" flight in spaceship to a "stationary" mode. When one needs to get to orbit, to spend some rotations around the Earth, to fly to the Moon or to reach another spacecraft to dock - it's "transitory", and when one needs to "stay in space" for prolonged time and one is doing some activities while in that state - it's more "stationary". Space stations were built in the second decade of human spaceflight, and presented a platform for focusing more on science and less on the spaceflight itself.
A lot was learned in that decade. We saw that we could work in space for weeks and months at a time - and working in space stations is much better than in manned spaceships of 1960s. Spaceships were - and are - intended to carry people from Earth to space, from Earth to the Moon, back to Earth, but spaceships are worse as places for prolonged stay in space. We need some rooms in space where we could stay for long time, better than just in the spaceships. Even though the Moon is rather far, and we didn't fly to the Moon for a long time since early 1970s, we would still want to fly to space, to low Earth orbit, and we would need a destination there, where we can go and work from. We need the home on orbit. And space stations can give us that home.
One of direct and practical lessons with space stations was that they are hard to support, when all the consumables onboard had to be launched with the station or come with the expeditions - that's how those prolonged visits of the station became known. After all those resources were spent, the station had to be deorbited.