Just in case: people in USSR were not equally payed. Peasants had minimal salaries, I think, whilst miners, for example, had huge salaries (in relation to the average). Renowned singers, scientists made much more money than "ordinary" ones. Some people took one-off tasks, which were well paid (at the time I was in kindergarten, the father of my girlfriend painted a local TV tower, and in several days got as much as my parents would earn for half-year). So strong, enterprising men definitely were richer. There were a lot of skews in those payment schemes, of course.

Some were stealing goods from the very place where they worked. For example, peasants were stealing fodder, etc.

Antonio, I heard only one explanation of such sudden demise of USSR: real chiefs of the state (not Gorbachyov) decided that it's no more amusing to play modest men with lofty ideals, and it's time to try something new.