Ryan_m_b said:
...You said they mostly live in one city? Even if they have outlying towns they'd have to be spread across potentially thousands of kilometres. That means you're going to have to have long supply chains to bring back goods and ship supplies to these places which is going to be quite expensive. Not to mention fragile, how long would your city survive if the enemy took out a few of these outlying towns? Also how many people does it take to operate an assortment of mines, quarries, oil fields etcetera? Especially as procedures, tools and workers in one field (i.e. chalk mining) might be totally inappropriate in another (i.e. uranium mining).
Yes long supply chains. Expensive? Not so bad, bulk ship transport is actually quite cheap. In Poland a few years ago there was a scandal - it turned out that importing coal from Australia was cheaper than mining it locally. (communists were explaining us for generations that coal was our main national asset...)
Damn, I just found other vulnerability that I haven't thought about it. One WW2 U-Boot would be able to choke most of such transport.
How would survive? For a while - no problem, there would be stockpiles - intended to survive a minor misfortune (like a big collapse in mine or drowning of two cargo ships in row). An captured mine would be indeed a problem.
Except from turning such crucial mines into a fortified regions I don't see a way into being able to defend them.
Sweden, like many rich nations, is reliant on trade for its economy to function. You seem to be trying to have your cake and eat it to: a nation that has the low population and high GDP of a real world nation but without the global market those nations need to function. Really what this boils down to is that a nation can have a small population, can have a high GDP and can have low levels of trade but it can only have two out of the three at anyone time. Bonus addition: it can be low tech, at which point it becomes "pick three out of four".
One thing. I do not to drop Sweden economy on this planet and pray for a miracle. ;) I fully see the part that economy would be terribly hit by lack of external trade. I try rather to counterbalance it with higher gross capital formation rate, higher human capital and automation.
Let's disaggregate GDP:
-farming, agriculture, mining (a few % of GDP) - perfect conditions
-industry (30% of GDP) - serious problem here
-services (over 75% of GDP) - fine conditions
So the real hit would be concerning stuff produced in small quantities. Like unique manufacturing equipment.
Other question - which level of tech improvement would you consider as realistic for a small, separate country, which is well managed, well educated and treating maintaining high tech as high priority?