[javert]

"Corporatocracy" cannot be an appropriate name for a system where most corporations are the victim of a few corporations that have governmental powers.

So, "corporatocracy" is not a valid word.

It would be like calling a dictatorship a "manocracy."

On the subject of political vs. economic systems: a specific political system implies a specific economic system, and vice versa, so there isn't the distinction here that you think.