I dont think "a lof of people want the USSR back".... Stalin died in 1953, that was 66 years ago.... To "miss him" one would hvae to be well over 80...
Some reasons why a few people might miss the later USSR (of the 70s or so) :
- Stability / no concerns about the future
- Job security and full employment
- Scientific achievements
- Great power role
- Equality of opportunity regardles of ethnicity
- No rich/poor divide
- Money was not a concern, nor a value
I think it's more about psychology. People always see other periods of history as beautiful, heaven-like worlds, where everyone would be accepted and every work'd be paid properly. It's more relevant to Russia and other developing countries, which are now facing many problems.
Maybe not in Donald Trump - Louisiana swamp poacher or Mukesh Ambani - starving South Indian farmer sense but very much there. In communist countries (the ones that follow communist economy) riches come with power and position in government. Central committee and politburo members all had private dachas in Moscow suburbs while the urban population lived in the pigeonholes of government apartments.
Aside from everything already said and the fact the OP apparently jumped from 30's to 1991 and omitted half a century - old people remember the time of their youth, the best time of their life/ better young in hell than old in heaven. By the way great part of 90's in many aspects were idd the hell for many, young and old.
I have the idea that the Soviet Union was far better in every sense when it comes to the Central Asian Republics, especially Turkmenistan and Kyrgyzstan. Also the predicaments of Armenia, Transnistria and Nagorno-Karabakh wouldn't be there if not for the collapse of Soviet Union.