The two examples are temporal inverses of one another. In the situation of capitalism collapsing into government-granted monopolies, free-market capitalism is the first stage, and state central planning is the second stage. In the situation in China, the first stage was a vanguard-party-led society governed by a dictatorship of the proletariat that carries out state central planning, and the second stage is mostly free-market capitalism.
I don't think that anyone ever tried to use "Leninist system" to mean "a system where the government is not corrupt", but maybe I just haven't read enough of Lenin?
The only thing this had to do with is what incentive structure each set up and what the expected outcomes of those are.
Leninism:
Concentrate the power into professional revolutionaries, a vanguard, to lead the people into making the "correct" choices.
Incentive: Keep this new and unprecedented amount of power indefinitely.
Outcome: Corruption of whatever ideals they might have had.
Capitalism:
Concentrate the wealth and thus power into businessmen/corporations with the purpose of keep accumulating wealth indefinitely.
Incentive: Use the power and influence of wealth to do just that, accumulate more wealth.
Outcome: Manipulation of rules, regulations, and the market.
This is what they are. This is what we've seen for more than a 100 years for both. This is what they are accountable for.