No, they don't. You are just being ridiculous now.
We do have oligarchy elements within the United States government today. These are unconstitutional organizations, such as the EPA, the NEA, the BATF, elements of the FAA, elements of the FCC, and a host of others.
Nothing gave Congress the authority to create these departments or to give them the power they have.
They do not control everything. Indeed, there level of control is quite limited in scope. Many simply choose to ignore them on some level.
Capitalism is not an oligarchy, neither does it form oligarchies. Indeed, it needs no government at all to implement it.