Is the structure of the federal government the root of the problems or is the occupants of federal offices that are the problem.
Aside from Amend. XVII, it is the latter.
Correction:
Is the structure of the federal government the root of the problem or is it the occupants of federal offices that are the problem?
By your logic, many amendments of the Constitution are unnecessary, not just the 17th.
Do you think the 26th and 27th Amendments were necessary and do they work as intended?