You make it sound as though being easily manipulated by people with a lot of resources is a character flaw, rather than a characteristic of all humans throughout history.
It is unlikely (and maybe even undesirable) that we are going to be able to easily overcome our inherent susceptibility to influence. Therefore if we are to improve things we must recognize that this is part of who we are, and design our institutions accordingly.
Realism on all sides of this debate would be amazingly helpful. For instance, this continual disingenuous cry of "the corporations!" is stupid on its face. Are corporations autonomous intelligent entities outside of the will of powerful people? No! It's powerful people lobbying for rules that will help them. Destroy the concept of corporations tomorrow and you will still have powerful people who bend government to their will - you'll probably just have fewer people with much greater shares of power.
It is unlikely (and maybe even undesirable) that we are going to be able to easily overcome our inherent susceptibility to influence. Therefore if we are to improve things we must recognize that this is part of who we are, and design our institutions accordingly.