Corporations make the rules, capital P “Politicians” make them official and enforceable. The police enforce these corporo-fascist rules. The people actually provide very little of the money to traditional candidates, most of the funding for campaigns comes from corporate donations, hence the reason these corporations have so much of a say. Senator Sanders’ campaign was important because most of the money came from average citizens, and therefore actually made him dangerous to the institution of modern American “democracy”. Institutions will protect themselves first, this is why people like Sanders and Senators Murphy, Warren, and Kaine believe the smart money is in changing the Democratic Party, and not starting or endorsing a third party (at the national level, things are different at the local and state levels). After all, the Democratic Party also has the organization and the infrastructure that third parties don’t.
In response to business politics, traditional businesses are, by nature, fascist organizations. All power lies at the top. Some owners/managers/proprietors might treat their employees better than others, but they’re still the ones calling the shots. Rule makers are most frequently rule breakers because there’s literally no power beneath. This is related to the current political climate because of corporate involvement in American politics, but otherwise has very little to do with it.
People forget that corporations want them to feel powerless. They want them to feel like their votes don’t matter. Corporations want you to believe that the only way to feel happy is to buy their product or service. It’s directly related.
Tl;dr: corporate interest in politics is the reason politics are in their current state. If you don’t like it, get involved, encourage others to get involved, and support efforts to remove corporate money from the political process.