Well, strictly speaking, it all was just a consequence of absolutely corrupted, inefficient, idiotic and "not-working-even-in-theory" economic model of SU. And arms race had much to do with that - best scientist, engineers, technicians and other specialists were working on the military contractors, and civilian sector was fed with worst leftovers of their achievements. So it was arms race, oil prices, total lack of any political will in SU's government (and simple reason at the same time), and some other factors - each of them played it's role.
By the way, after the Olympic Games of 1980 in Moscow there was a huge disappointment all over the country - people thought that it was a promised "communism", but after the Games it ended as promptly as it began. It was a true "crisis of faith" even for most "hardcore communists", and it all went downhill even faster from there.
Why your post was modded Troll, anyway?