While Salyut-7 was on orbit - it was deorbited on 7 February 1991 - another station was launched by USSR. 20 February 1986 Proton rocket launched base module of Mir space station - the first station of the third generation.
While the first generation represented the first "homes on orbit" and the second generation allowed long-term missions with a variety of activities, the third generation extended those stations to the sizes bigger than what could be carried by a single launch - of even a largest available rocket. Mir base module was launched on Proton, but the distinctive feature of it was a docking section, which allowed 5 other modules - even as big as Salyut or TKS - to be docked to it. On another end of base module there was another docking port, for one more spaceship. In this way Mir base module was planned to be a center of expansive station, with different modules specializing on different activities. That's what was gradually happening over the following years.
Salyut-7 had a long life with many unusual events, but Mir had it even more. Mir may be considered a textbook example of a long running program which has to deal with circumstances unforeseen by its designers. In order to remain relevant, Mir program had to thread water into many unknowns, succeeding with some, retracting with others. It gave to the world spaceflight tremendous lessons of the future, fortunately for rather affordable price.