That's not the reason the courts and legislatures have "dummied up." There have been cases of lesser executive being found ineligible, and NONE of their official acts are rescinded. All are upheld on a the doctrine of "de facto officer," on the rationale that any attempt to unwind the official acts would create chaos.
The reason the courts and legislatures pretend this is settled in favor of McCain, Cruz, Obama, etc. is face saving, and the governing institutions view themselves as part of a globalist, anti-nationalist transition team.
Thats a plausible theory. Question is how do we get our Constitutional form of government back?