We have an OTL example of a western country that was pretty command-and-control Socialist and that was the UK pre-Thatcher.
Funny, but no. Official Laborers were already more Social Democrats than Socialists at that time (the difference is enormous). And inside there was a huge number of factions (including the liberal one - which later emerged as a "Social Democratic Party").
The reason for the economic problems was not in the state regulation, but ... that all their reforms did not affect the basic principles of the capitalist economy. The Labor government is known for its nationalizations, but only large enterprises connected with transport and heavy industry were nationalized, while the bourgeoisie received significant compensation (which is unprofitable for the economy, and contradicts the principle of expropriating expropriators). Moreover, most of these enterprises were nationalized only for that .... in order to remove them (in the ownership of the state, as a rule, non-profit enterprises came into being) and return them to the former bosses. This is more like a deal between the capital and the state - at the same time the state was at a loss. Remember another war in Korea, where Britain had no reason to participate. In other words, the whole "Labor Socialism" consists only in a mediocre financial policy and deals with the bourgeoisie, while it is simply necessary to take it away. This is in the first place.
Secondly, the Soviet economy in many ways was the second economy in the world. Yes, basically it concerned heavy industry, but also in the sphere of consumer goods, statistics is not a depressing table. The main problem of the Soviet economy is the mediocre distribution of goods (when I do not know where to put fish in Komsomolsk-on-Amur, and Sredlovsk does not have it).
Thirdly - that before the backlog, then in the beginning of the USSR was in the worst conditions. But nevertheless, in the sixties the USSR had real chances to get ahead .... Even in the field of cinema and design of the USSR, if not glittering, it kept at the European level.