I don’t think it’s particularly productive to back up controversial claims within the Marxist current with statements like “it’s clear that xyz” or “it’s without question.” These topics are controversial because they aren’t clear and are questionable claims.
I really appreciate this and you are right - the claims I made do go against ML theory, and whether something is right or wrong in this case is dependent on one's views and perspectives (as in intra-Marxism) rather than cold, hard, unquestionable facts. I will definitely try to avoid such loaded language in the future.
In essence, I do largely agree with you - the material conditions in the historically socialist countries (USSR specifically in this case but can also more or less be applied to others) be it their peasant problem or being isolated due to international revolutions failing did require them to do what they had done and develop using state capitalism or "building socialism in one state", and they were successful in that regard. Same applies to the anti-colonial national liberation movements - they were successful and historically progressive and indeed should be celebrated.
However, the issue that this is a win for (state) capitalism and all the baggage that comes with it rather than actual socialism, given how socialist mode of production was never realized and arguments such as "people's billionaires who will get punished by going against the party" or "the economy was nationalized" don't define socialism. Wage labor remained (therefore surplus extraction too), commodity production and markets both within the country and interaction with international capitalist world market had remained (Why Russia isn't socialist talks about this). One could also make an argument that even in those countries where capitalists got done away with (which is a proletarian W) but state capitalism persisted, the functions of the capitalist remained and were carried out by mere managers, like how Engels in Socialism: Utopian and Scientific points out:
Partial recognition of the social character of the productive forces forced upon the capitalists themselves. Taking over of the great institutions for production and communication, first by joint-stock companies, later in by trusts, then by the State. The bourgeoisie demonstrated to be a superfluous class. All its social functions are now performed by salaried employees.
And again to reiterate, rather than being a win for socialism, it's instead a win for a regressive form of it which is state capitalism that's comparable to social democracy.
As about your point about the rejection of AES, that's not my argument at all - instead of rejecting any attempt outright and waiting for a perfect revolution, one should instead support all revolutionary attempts but, most importantly, realize when the revolution had failed/ended instead of clinging onto false hope which is something that ML's tend to do at least from my perspective. Of course, when a revolution fails depends on ones perspective, but from mine it's when the proletarian revolution (which must be internationalist) fails to spread and a country has to start fully focusing inwards for its survival within global capitalism and the inevitable participation in it, like what happened in USSR in 1920's - at that point, it's only a matter of time until the country falls to revisionism, degeneration of socialist ideas and the aforementioned full reintegration into global capitalist system.
That being said, I really do appreciate your responses, even though some of them might be too long for me to respond to.
I don't have enough hubris to say that I have all the answers, especially when it comes to the way forward - this is something that's up to the revolutionary party collectively to decide, but I do disagree with the ML's theory and methodology, especially with "Socialism in one state" or the 'worship' of State Capitalism. However, if you had a gun to my head, I'd probably manage to squeak out something possibly infantile like this:
When it comes to proletarian revolutions that attempt to build socialism, internationalism is a necessity (both to allow international trade to help meet everyone's needs and weakening of the capitalist global order and reducing them as a threat) - once proletarian and an international party takes power, the focus should be in coordinating/exporting the revolution worldwide mostly via the support of proletarian movements, else it will get isolated, start playing for survival, have to adapt to capitalism and eventually collapse or degenerate as seen historically.
Also, instead of treating state capitalism and markets as a transitional phase that is constantly expanded/built upon, it should instead not be viewed as legitimate and rather something residual, to be replaced as soon as possible. In theory, this should allow for a certain amount of goods to be produced for use, and goods that are more scarce could be produced as commodities and rationed through money.
Once sufficient economic restructuring for transition towards socialist mode of production is done, that's when the transition towards non-accumulative labor vouchers can be done, which should eliminate the law of value and capital relations.