The idea from what I gather is that the country is capable of supporting itself, and did for centuries, and shouldn't let industries wither and die for short term profit that would kill off industries that allow that ability of self support.

Because being self-sufficient and having a good import/exports sheets makes you more resilient in the mid- and long-run that having all the chips that local customers demand.

You can always allow for more chips whenever you really want. Reversing a damaged trade deficit or self-sustainability? Not so much, and not anywhere near as fast.