There are many factors that determine how a person will vote. The main reason is party loyalty, but people also tend to vote on one issue that is important to them and tend to ignore all other issues. The other problem is most people tend to ignore the campaign process when the candidates are traveling around the country making promises that they will never keep, making false accusations and insinuations against their opponent, agitating people to vote on religious issues, social issues and other things individuals may be passionate about - then at the presidential debates they lie their asses off to the public when they know that the only exposure to them by most voters is based on those debates.
Most people believe the lies and pay the consequences after the person is elected into office.
The worst is the congressional members who do what they want after being elected, or whatever their benefactors want them to do, instead of what is best for the people in general. This certainly was evident over the past 4 years with all the obstructionism by one party against the other without any consideration for the american people. Nothing is likely to change in the next 4 years and beyond.