Perhaps the quality of candidates is a reflection that the competencies of candidates are irrelevant to government in America today. All Congress persons have to do is what the organizations that bought them tell them to do.
It may also be the case that the demise of democracy in America is a sign of a revolution in world affairs in which nations and national governments are less important than transnational corporations, reflected in the fact that the Supreme Court gave corporations citizenship, and many of these corporations are owned in large part by foreign interests.
We rarely recognize a social revolution when we are living through it.