TSMC is not making chips for the Defense Dept. because they are still using 65nm chips, which are 2005 technology. TSMC is heading for 3nm technology next year.

Defense and JPL/NASA require proven technologies which have proved stable over time; the latest Mars rover uses a Powerpc chip from 1998. The most important requirement for Defense chips is that they can handle EMR (electro-magnetic radiation) resistant, because that means they can survive a nuclear blast.

Check this video for details: https://youtu.be/oSNhk4TflKA