Generally old chips are good, depends on the purpose. Some things like the f35 would like to use TSMC’s fabs. But not every chip is for only processing and larger process have their advantages for certain applications like power, analog, and em hardening
Also the fab for a 20year old process is probably easier/cheaper/faster to re-build in case the enemy destroys it, than the fab for 5nm process you've been building for 4 years.
Nevermind the nation probably has more than 1 of such old fabs, so it can't be technologically decapitated by destroying a single precious 5nm fab it has.
