Perhaps it's time to stop using appeals to purity and acknowledge that this is how capitalism functions in practice everywhere it's been tried. Entire books have been written on the subject of why capital concentration is a necessary product of capitalism, and how capitalists use their wealth in shape society in their own interest. The government ultimately represents the class that holds power, and in a capitalist society it happens to be the capital owning class. That's why even when regulations are enacted, they're always dismantled in the end.