What if their coexistence on such a large scale is the real problem? They each rely on the other for power. A corporation is a government creation, with legal definitions which protect it from market forces. And government laws and regulations are largely designed by corporate special interests.

It is a vicious cycle which arguably fits the definition of fascism. The government doesn't own the means of production, but it regulates industry to the point that it might as well. A corporation can work through the government to make any law or regulation it wants which will give them an unfair advantage or kill a competitor. The government even directly hands corporations money in the form of bailouts, subsidies, and grants!

At this point, it is impossible to disentangle big business and big government. So when we talk decentralizing institutions, it is not just the government which needs to be split up.