The reasons should be obvious. Coronavirus would not be the issue it is in economic terms if we did not have such an interconnected world, where supply lines are stretched to their limits so that many companies are at risk from the slightest disruption to their systems, which coronavirus is already creating, and which could get much worse.
Far better to have entirely local economies. So that when the local farmer drops dead then all starve in that area.
Hmm, what’s that? Security comes from having multiple suppliers? Gosh, that’s right! So, having all the world as a potential supplier is safer then, right?