That's completely wrong I'm afraid. If you actually read Marx, you'll see that a transitional state is absolutely necessary. This is the state that withers, and it's not something that happens overnight. Furthermore, it's quite obviously impossible for a socialist state to wither when the world is dominated by a capitalist hegemon that actively works to undermine any socialist experiments. Only after capitalism has been defeated globally can there be any talk of the state withering.
Furthermore, it makes no sense to treat everything Marx said as dogma. A socialist state is objectively a better scenario than the tyranny of the bourgeoisie regardless of what flaws it may have. Improving things in practical terms is always more valuable than pining for utopian solutions that are unreachable.
Orwell wrote infantile fiction, and it's frankly silly to call that a critique of Leninism. Once again, the reality is that socialist states, whatever faults they may have, are a tangible improvement on capitalism.
Coming back to Russell's scenario, here's the plan USSR had for reducing the work week. And what business tendency are you talking about in a socialist state such as USSR exactly? The industry is owned by the state, the purpose of the industry is to produce things for people living in the state. Work isn't done to create wealth for people who own businesses, there is no inherent incentive to exploit the workers.