Rules TBD.
Stalin was initially receptive to Lenin’s New Economic Policy. I’m not familiar with the whys & whos of its retirement.
I always assumed the serial crises and upheaval of WW2 and the Cold War put experimental policies like that on the back burner and they just never got picked back up.
That's been my understanding as well, the NEP was abandoned because there was a realization that the USSR would not be able to withstand a war with Germany without rapid mass industrialization.
And the state of emergency was very hard to lift after given that the US got all the Nazis to work on sabotage against the Eastern bloc, not to mention had developed a nuclear weapon and refused to rule out a first strike against the USSR.
Exactly, USSR was under siege from western capitalist powers throughout its whole existence.
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There are other countries that followed a similar path; Japan, South Korea and Taiwan
Except Japan and occupied Korea did not follow the same path, meanwhile Taiwan is not a country.