The question is rather what is a healthy level of inequality and should the government work on increasing inequality.
Most people under estimate the amount of inequality in the US, this [1] is an awesome video illustrating it. Also there is some interesting research on modelling inequality as a phase change process and that there exist some point of no return after which inequality only increases towards a oligarchy/plutogarchy without a revolution type event [2]
[1] https://youtu.be/QPKKQnijnsM [2] https://www.scientificamerican.com/article/is-inequality-ine...
The fact that income and wealth inequality are different in different countries is proof in and of itself.
This is an _incredibly_ rose-tinted view of the Soviet Union. I would suggest researching Waldsiedlung as a starting point.
However to say that government policy can't substantially reduce inequality is patently absurd. The government has the power to take things from people, every year, in taxes.
Wealth inequality is a symptom of government policy, nothing more.
[1] https://en.wikipedia.org/wiki/List_of_countries_by_income_eq...