I think you are badly overestimating how much the fact that the USSR had money means that they also had functioning markets. The two are neither synonymous, nor does either require the other.
Remember that money has no meaning other than the keeping track of things.
I disagree. Money isn't just an elaborate system of tokens, it possesses a uniquely circulatory character. If there is a system of circulating money, then it necessarily follows that there is a market for it to circulate
in. The USSR possessed just such a system, albeit one that the state attempted to obscure by artificially "submerging" money when it came into the hands of the state, to give the impression that it was simply allocated at one end and redeemed at the other. The internal plans of the state economies were still primarily based on financial calculations- the much touted "material balance planning" was basically a farce using internal forms of credit and shadow pricing.
Now, it's true that this doesn't amount to a "functioning market" (whatever we mean by that, exactly), but I didn't claim that it did. Merely that a market existed.
If there are shortages of some goods year after year, and the price isn't rising and the producers not making more, then the signaling mechanism has failed. And if there are goods that go unsold because no one wants them, then the signaling has failed. Despite the fact that there was some signaling, some monetary, some not, does not mean that there are actual functioning markets. And all the other aspects of the Soviet economy. There is very little that you can point to in what was going on in the USSR that resembled markets, except the black markets. And you can see that even more in what happened just after communism (what they called communism at the time, let's not go down that road again just now

)collapsed. Almost immediately after state planning was gone, empty store shelves were filled. That right there tells you that the state was failing at making a reasonable facsimile of working markets.
That does not in itself suggest the absence of a market. It's nothing that can't be explained as a monopolistic megacorporation with state backing (that just happens to be incompetent and bad at prioritising), while your model demands an all-powerful autocratic-totalitarian state of the kind that the USSR ever so patently was
not. Given that the similarly (if less pronouncedly) challenged Western Keynesian systems were brought to their knees during the 1970s, at same time as the Soviet and Eastern Bloc economies began to come apart , it seems entirely unnecessary to construct some narrative that attributes there woes not to the general failure of hard interventionism in this period, but to some totally distinct set of mechanisms that just happened to emerge at the same time and in the same broad fashion.
Economists, but they're not wrong. Take as an example small craft unions: whose interests are they looking out for? "The workers?" No way! They want to squeeze out every penny they can for their members. Who do the farmers lobby on behalf of, the consumer for lower prices? Nope! It's always for a subsidy or price support.
I don't follow. How does the fact that people pursue self-interest, and that this can lead to conflict which does not follow class lines (which I'm not sure is being denied by anyone?

) imply that
everyone is
always in competition with
everyone else. Unless perhaps I'm overstating the level of conflict which you imagine as being present?
(And thanks for being honest about the boundless wisdom of economists, I guess. Who needs interdisciplinarianism, eh?

)
It does sometimes seem that the only difference between the capitalist and the communist is the former thinks the rich works harder than the poor and the latter thinks the poor works harder than the rich. They both use the same language of "freedom" and "human rights".
I've never heard a proponent of capitalism argue that the effort expended by the rich and poor are proportional to their income. That's patently impossible. What they argue is that
this doesn't matter, which is something altogether different. They may also happen to claim that the rich work harder and this somehow makes them morally superior, but that's because the sort of people who usually make these arguments are deeply involved in petty populist moralising, not because its a claim that plays any particular role in formulating their politics.