Yes but how long did it take to get to that point? It took an incredibly large amount of time for the party to become corrupted enough to require the corruption crackdowns, which were essentially purges of this.
Depending how you count it, it took about 30 years, but really longer because Dengist-types preceded Deng's turn at the reins (they brought him from being in informal exile to toppling the Gang of Four, after all). I wouldn't know where to count to get an accurate estimate, but perhaps it would be 50 years, since the Hundred Flowers campaign's subsequent crackdown probably got rid of a lot of the ones who were festering from even during the Civil War. How old are these measures, anyway? Does this even apply?
Anyway, I think that overwhelmingly the corruption crackdowns were against people who were actually corrupt rather than ideologically compromised, and you happen to mention someone who is the inverse next.
Post ww2 the party became a "party of the people" and Kruschev deemed it was of the people because the people were participants.
It's actually worse than that. He actually said the Dictatorship of the Proletariat was over and they were now running a "Whole People's Party" as in supposedly representing the interests of the entire population, and he used this as cover for beginning the restoration of the bourgeoisie.
All ideology became muddled. It was a mess. This was because no enforcement of party line, no prevention of those uneducated in marxism was undertaken.
I would argue, based on the above and on the history of destalinization, that it was not just muddled but in fact deliberately revisionist. I don't really know where Khrushchev thought he was going with doing that while continuing to fight the west (seems like the perfect opportunity to be a compradore), maybe he just bought into pro-market propaganda. Of course, by the end of his time in office it certainly was also muddled because that's why he got ousted: for being directionless.
But part of my point is that even this dingbat revisionist and what was ultimately his substantial backing were all in the Party prior to the death of Stalin. Others, like Bukharin, were Old Bolsheviks themselves! This was a problem that wasn't started by some freak accident letting Khrushchev through, it was already consuming the Party before Khrushchev did anything and perhaps even before Stalin did.
You have not proposed alternatives?
I'm actually fine with gatekeeping a vanguard party if policy decisions are made by the people, even if that means they wouldn't do something as wise as the vanguard could wish of them. Ironically, Xi writes about just that scenario in a document that I have been looking for for like 2 years called something like "We Must Follow the People into the Fire". This is ironic, in my opinion, but we don't need to get into that and really probably shouldn't. My view is basically that of the primacy of democracy: either you give the people the ability to decide policy or you give them the ability to choose policy deciders (or vote for the people who vote, as I don't have a problem with that part of China's system).
I mean, come on, China's already got compulsory education requirements. If it's so important to have your definition of a good Marxist education, give it to people! Not that this answers the issue, since in many rural places people don't get all that much schooling still, which means this would still put privileged people on top (or further on top) politically.
Historically, I am referring to the Bolsheviks and then the Communist Party of the Soviet Union
Generally, a vanguard party is the forward segment of the population that is educated on and dedicated to the project of social revolution and agitates and organizes among the general population towards this end, and though it becomes something more administrative when it has control of the state, those two functions remain, as does the need to not (try to) compel the masses into something they don't want to do. There can be no benevolent tyrants, just educators who operate with the popular mandate.