Nonetheless, even today, the vast majority of countries are not self-sufficient on defense infrastructure, and this has been true for most of the modern era. The most obvious deficiency is in naval terms: the number of countries who have enough of a navy that they can do something about "my shipping is being attacked by pirates" without help from other people is plausibly at most five (US, UK, France, Russia, China), and I have my doubts about half of those.
Nonetheless, even today, the vast majority of countries are not self-sufficient on defense infrastructure, and this has been true for most of the modern era. The most obvious deficiency is in naval terms: the number of countries who have enough of a navy that they can do something about "my shipping is being attacked by pirates" without help from other people is plausibly at most five (US, UK, France, Russia, China), and I have my doubts about half of those.