> how much of security critical U.S. consumption can that cover?

What US can't source for F-35 locally are Xilinx FPGAs at either 65nm, or 40nm nodes.

The question is not in node size as such as having an FPGA process capability.

FPGAs on generic CMOS don't work great. The ability to tweak, and optimize the process specifically for individual design is huge for FPGAs.

Intel with their CPUs are very much in the same situation, but in reverse. They cannot move from "hand polished" proprietary processes they've been developing for decades to anything else.