I must confess a considerable gap in my own knowledge of Soviet history in the pre- and post-war years, so I can't really claim that anything Matt says is explicitly wrong, but, he does make a very good point at the beginning that to assign blame or praise uniquely on Stalin alone for the Soviet Union's economic rise and misdeeds is tantamount to religious mysticism and bears the same pitfalls of great man theory. Stalin did not act alone, nor was the USSR run by the whims of one man.
As for Stalin's loser cowardice in the immediate post-war to not better exploit his own state power to act as a better contrast against the influence of Capital - I'd like to read some good sources that cover this as another potential path. Ultimately, I still agree with Matt that debating the merits of Stalin is pointless and exhausting in the present.
They/he didn’t have a lot of time, there was mini-famine post war, they had to fix shit after it was bombed. Planning wise they were doing kinda okay, unfortunately the guy who stalin liked to succeed him died unexpectedly, so it all gone to shit basically. As well some small plans for democratization
He says in the beginning that in building the USSR Stalin shouldn't be idolized or mystified as a great man but then proceeds to lay the post-war failures directly at his feet. If he really thinks that the communist party became bourgeoise because they didn't want "real jobs" then that is an implicit statement that the vangaurd party is always doomed to fail to lead the dictatorship of the proletariat.
I don't want to get into the habit of psychoanalyzing people but, if we accept that history is as much a reflection of the present as a record of the past, I'd say that alternative histories such as this are more a reflection of their author than the material conditions at the time. Matt is bourg-ified and doesn't want to work a "real job" and is projecting his anxieties about his own material conditions onto a totally different circumstance.