Fairchild Republic is all gone. All the dies and tools to make the A-10 have been destroyed. We'll never see another new A10, for sure.
Boeing rebuilt the tooling for the wings for the recent re-winging effort.
The stresses on the fuselages are low enough that they’ll, functionally, never wear out. There’s not even a need for new engines since the A-10 uses the same ones as the now-retired USN S-3 fleet. So, again, plenty of spares.