Wage labour was in place in the USSR. Surplus value was extracted from the labour of the proletariat in the USSR. Thus, capitalism remained in tact. This surplus value went to line the pockets of the state as well as mangers of factories who were often paid 10x or so what the workers were paid. Even if that money were shared among everyone equally, it would still mean the capitalist mode of production was still in place.
The means of productions didn't even had worker's ownership in the USSR, they continued the model of a manager with power to fire, hire, demote, promote.
The extraction of surplus value still happened and the worker's ownership over means of production didn't happen which makes the USSR a capitalist state.
In the late 1940s the various state industries were mandated by law to make a profit because state subsidising was now over. This is really just the enshrining in law of what was already a material reality. Russia, and the USSR, were involved with capitalist accumulation before and after the October revolution.