The US has no form of vote of no confidence. So therefore no way to have consequences for bad governing outside of the voting period, which has its own problems. Importantly here is the need for quick backlash rather than wait two or more years to choose someone else (if there is anyone else allowed to be a pick).
A lot of the flaws in the government are inherent from the beginning because there were certain expectations assumed, and that a document of rules can't be perfect the first, second, or even only a third time. It needs consistent revisions to keep up with the needs of the group it is designed for. This is where the biggest failure has happened, and can be attributed to lack of attention, not wanting to change what seems to work, sacred holding of what was never meant to be set in stone, or just that it often benefited not being changed at the time by those with the power to change it.
Add to all that a very short attention spanned public, fine tuned to be ignorant and forgetful as well as easily manipulated by the simplest of sound bites.
The rot is in the walls. Not that the American Experiment was a bad thing, it's just that it wasn't maintained and updated, so you get eventual decay.