No any country can have everything they need now, it's Globalization! But if any country treats other countries (especially the high-tech countries) as enemy then you are out, and it's impossible to have everything yourselves. Even you have some important tech, then the cost will be very high since you only have a small (domestic) markets therefore you can not compete with other countries. You don;t need to consider the cost of Nuclear Bomb, but you need to consider the cost of chips, IC, device, etc.