Fully agree on the root cause, but not on the solution.
We should strive for extremely limited power by our public representatives, so their corruption impact is reduced to a minimum. But not only limited power, but also limited budget access, as an extension to limit that power. And that actually means reduced taxation.
But at the same time, the budget for justice system needs to increase. It should be most probably the strongest branch of the government. Delayed justice is one of the most common ways of injustice.
Corruption within private companies is irrelevant, as the main ones to suffer from it are usually shareholders. Government has no say in that. That is unless companies break the law, and that's why a strong Justice system is necessary. With a reduced size of the state there's also way less risk of private companies and individuals to corrupt public representatives.
Monopolies are not always a negative outcome on a free market if the company in Monopoly situation reaches that position by offering better products within the law. However they can be specially dangerous when they're artificially created by the Government (e.g. allocation of a common resource to a specific company --> corruption almost always follows).