This is a very complex subject.

Firstly, In a pure free market the "Corporations" wouldn't exist.

Corporations are commonly associated with "businesses", but corporations are pretty much any legal "fictional entity" formed by the government.

For example if you live within the borders of a officially recognized town or city you live within a "Municipal Corporation". It is the fact that they are incorporated and recognized by the state that gives them ability to do things like hire police and create ordinances. This is why they call unofficial towns "unincorporated areas".

What makes corporations significant is that there is a "legal personhood" created by the government that is separate and distinct from the people that run, own and are hired by the corporation. It has a legal life that is separate and distinct from them.

With businesses there are various specific types of corporations, Class-C corporation, limited liability corporations, etc. Collectively they are called "General Corporations".

General Corporations didn't exist until the 20th Century. There was a few precursors, but they were mostly repealed. The first modern general corporation law happened in Delaware in 1899 and their favorable corporate law is why a lot of big businesses still incorporate in Delaware.

Prior to that business corporations existed, but they required special legislator. They were created for a specific purpose and had a time limit. Meaning that after 20 years, or whatever the legislation said, the corporation would "die". Prior to modern monetary debt system towns would do things like request the state to allow them to create a shared stock corporation to do things like finance the creation of a bridge. They would get investors, build the bridge, charge tolls for it and then pay dividends to the share owners until the corporation dissolved and the bridge was awarded back to the county or town or whatever.

Which is to say that corporations represent a merger between state and business interest.

For example the British Crown created the East India Company, which was a corporation, for the purpose of exploiting colonial holdings in Asia. And in this sense business corporations are essentially "mini governments" created for exploitation. They had pseudo-government powers and relied on the British Navy to maintain their monopoly.

The point I am trying to make is that the idea that "We need government to counter the greed of corporations" is never actually been a thing that is true.

Not historically and not in the 20th century and not today.

The way things worked out is very clumsy and messy, but over-simplified....

Large public corporations are a part of Progressive-Era politics. This is a anti-liberal (in the classical sense) agenda to curb the "wastefulness" of free market capitalism. They felt that all these small and medium private businesses all infighting and competing with one another constantly drove down wages and quality of goods and produced a lot of wasteful spending and investment. So in order to make America efficient it was necessary to consolidate everything into a handful of large businesses in each industry.

Along with this was the idea of "Wilsonian Administrative State" (look it up),

In 1887 Woodrow Wilson published a book called "The Study of Administration". The basic idea is that the USA Constitution was created for a bygone era. That because of the increased complexity of modern industrialized society we needed a Administrative State to govern the country.

He also believed that the "Separation of powers" was only needed because back in the 1700s politicians were part timers. They had commercial interests outside of government. This represented significant conflict of interests and thus it was necessary to have a system of checks and balancing limiting Federal power.

So to work around this we need Administrative Agencies run by appointees. This agencies would be "independent" and ran by professionals that would be well compensated for their actions thus would not need to have interests outside of government. They would be highly educated (mostly PHD-level) and we could rely on their independence, patriotism, education, and wisdom to guide the country forward.

Also because of all of this the constitutional division of powers doesn't apply to them.

This idea of "Administrative State" was picked up and adopted and implemented.

So during the course of the 20th century we went from having like 3 different Federal Agencies to literally hundreds. Well over 400. The exact number is disputed because of different definitions of what constitutes a "administrative agency".

All of this eventually morphed into what can be considered American Corporatism. Which came a bit later.

Corporatism, also called Syndicalism, is a economic system were the "producers" form independent corporations or syndicates. These syndicates then work together with a central state to manage the economy.

There are lots of different theories and approaches to corporatism. They generally call it "Syndicalism" when it is "left" (which is derived from French "syndicate" for representative) and Corporatism when it is more "right" (derived from Latin Corpus meaning "Body"). But they are essentially the same thing.

Corporatism was a popular political concept in the early 20th century.

Some corporatist regimes were:

Mussolini, National Corporatism, Italy, 1922-1945

Miguel Primo de Rivera. "Country, Religion, Monarchy", Spain, 1923-1930

Hitler, National Socialist, Germany, 1933-1945

Salazar, New State, Portugal, 1932-1968

Vargas, New State, Brazil, 1933-1945

Roosevelt, New Deal, United States, 1933-1945.

Franco, National Syndicalism, Span, 1936-1973

Metaxas, Third Hellenic Civilization, Greece, 1936-1941.

Peron, Justice Party, Argentina, 1943-1945.

The New Deal was corporatism for the USA. Corporatism is highly associated with Fascism, and people tend to try to lump all of them together. But that isn't accurate. They are all distinct and different in the level of severity and approaches.

One of the ways to view WW1 and WW2 was that WW1 represented the last gasp of European Empires.

WW1 involved the British Empire, the French Empire, the German Empire, the Austro-Hungarian Empire, the Russian Empire, and the Ottoman Empire. By the end only British and French remained. All the other empires were destroyed.

WW2 then represents a conflict between the various large models of administrative states that replaced them. American New Deal, Russian Soviets, Italian Fascists, French Socialists, Germany National Socialists, along with the British Empire that was undergoing massive transformations itself.

After WW2 the victors were essentially the American Corporatist model and the Soviets, which then was in major rivalry until the end of the cold war in 1991.

It was the American model that won in the end.

And if you look around the world... Almost all governments now declare themselves "Constitutional Republics" and embrace the same economic concepts and approaches that the Americans created.

Large central banks, regulated stock markets, large public corporations, etc.

All of this means that without Regulated Markets, Large Central banks, Fiat currencies, and Administrative States we wouldn't have Big public corporations.

This is why our government has to now "print" trillions of dollars every year.

This is what the bailouts for 2008 for the housing crisis was. This is why big corporations were bailed out in 2020 and allowed to stay open while small and medium businesses were forced to shut down.

Moving to pure fiat currency to keep it all afloat on debt is https://wtfhappenedin1971.com/

The Administrative State, rise of corporatism (typically referred to as cronyism in Libertarian circles), central banking, fiat currency, heavily regulated stock market, and public corporations... all of these are parts of the same big thing.

Government doesn't exist to counter the greed of these big corporations.

Our government works its ass off to enable the greed of these big corporations. They are all part of the same big team.