Julian S. Taylor. It's inertia and a dreadful lack of imagination. We have both. We have it in our minds that our two party system is set in stone but it doesn't have to be for the reasons you point out.
Individuals with real talent make an enormous difference and our election system needs to be sufficiently flexible for them to surface. The U.S. currently has opportunities brought about by both Trump and the pandemic. These upsets have provided the setting for change. Of course the opportunities have to realized and the window is open only so long. Our current administration has talent but unfortunately not at the top.
Many thanks