The exclusion of former officials was something too impossible to accomplish in their minds. The entire national apparatus would have had to disappear overnight and be replaced with something wholly new staffed with an entire compliment of office holders with no experience or knowledge of what had been in place to avoid former communists.
Solzhenitsyn is saying therefore what happened is the officials that stayed in place from a policeman on up, just said, well we are all democrats now.
By the time of the collapse it was probably true that there were few “believing” communists — the whole system was corrupt and believed bankrupt by those that ran it, that is why it fell away so fast.
Definitions of despotic relate back to Egypt as applied by the Greeks. Mary I of England sure came close in her killing efforts. A whole group of nobles or a people in general could consider a King evil, tyrannical or hated but some good effort can always be picked out in hindsight for that monarch.
We view religious persecution from the American prism. For England in the midst of the reformation it was the matter of national identity, dissent threatened the very existence of the nation and so it was punishable alongside treason. She was not the first, nor the last, only Catholic. By the 1st Amendment standards any random government in history would be despotic, except a scant few in recent history, that seem all heading to oblivion as nations.
The idea that the nomenklatura was somehow useful is of course conceivable, if wrong. A typical communist apparatchik was at best silently consuming his salary, usually a direct hindrance to useful work. What their beliefs were does not matter, really, because the sovietism of the post-war period had little to do with ideas of Marx and Lenin, and everything to do with the nomanklatura’s survival. So they survived.