Regarding the evils of the 19th century robber barons it should be noted that it was the government that helped them become all they were. Lincoln and the Republican party established corporate welfare as policy i.e. government funds "helping" private businesses for the general public good. Part two of that is that the close relationship of government and these corporations once established bloomed into government favoring special interests over the general welfare. Governors - bought and paid for used the power of the state - police and national guard to come down on the side of large business in labor disputes for example. One further point is that the large influx of immigration floaded the labor pool so business could dictate harsh working terms and low wages to workers - if you don't like it there are plenty of others who need the work. No question that human nature is corrupt but government is not a fair arbitor - it is run by people who like everyone else are corrupt by nature. Government is force and nothing else. That force has been allowed to be harnessed by corporate interests and that is why the founders knew the answer is more freedom and less government in all things. Things are a mess because we discarded the wisdom of the founders.
You make some excellent points but, as is always necessary, you leave out a lot of good points, too. First, in addition to being corrupt human nature is also good. It depends on which nature is nourished throughout life that determines which prevails. The spiritual side, as opposed to the physical side, of human nature is just as natural and more conducive to harmonious interaction when nourished.
Secondly, free enterprise, a.k.a. capitalism, has the unique ability to transform the selfish interests of the individual into a common good for all. The market is self-regulating and the abuses of one side (labor, management, costs, price, etc.) are soon mitigated by fluctuations in supply and demand. When government interferes with this natural market interaction the system breaks down. I am not in favor of unrestricted "Buyer Beware" but as long as government prevents the big 'uns from eating the little 'uns that is about all it can safely do.
When Charlie Reese was with the Orlando Sentinel I enjoyed most of his columns. Since then I find more I disagree with than agree.