Because of the influence corporate and upper-class money has on the ability politicians have to win elections, politicians become subservient to their “donors”. They begin caring more for the interests of their “donors” than the interests of their constituents: people like you and me.
Consequently, problems such as environmental destruction, the widening inequality between the rich and the poor, and lack of access to health care are ignored because solving these problems goes against the interests of the corporate and upper-class: raking up profit. To emphasize, this does not mean that the corporate and upper-class are “evil”. Simply, there is a conflict of interests between the upper-class and working-class that needs to be resolved before all people can be served by their respective politicians.
So, if politicians need money to win elections, and will do what interests those who supply their campaign funding, then it becomes apparent how to get politicians to listen to people like you and me.