Generally if your economy is healthy the general case should be that no part of a supply chain can ever get rich enough to outright buy another piece. If any one part was making too generous a profit that could build that kind of war chest, low barriers to entry and competition would quickly propagate alternatives that took less profit.

This is, however, why you cannot just have a strict free market. Some industries emerge - and will emerge - that are naturally hard to enter and compete in. But at the same time, you need to have the lightest touch necessary, because the same regulatory apparatus can (and does in spades today) be abused to prevent competition by industry incumbents. But again, it is hard to accumulate the capital or scale to control government unless you have one of those non-competitive revenue streams.

The important historic realization is that we have failed to police businesses that had such extreme margins, probably because at the time those invested in such businesses felt it was just the success of the American market instead of being a wound in society that would grow infected.

It's a little odd of a comment as well since there is a plethora of small business incentives that the big guys don't get.

It's much more complicated that what the OP laid out.