Greece’s economy is almost a dream example of the point [that imports matter for exports]. Look at their exports (in a handy visual form from Wikipedia):
Their largest export is refined petroleum/oil, at 9.4% of the total. Greece isn’t making that oil, it’s importing it, refining it, and sending it along. They’re also major exporters of aluminum products, which I understand to be a ‘byproduct’ of their relatively large sources of energy, but they import the bauxite. I also can’t see how the packaged medicament industry in Greece doesn’t require imports of capital for everything from industrial fermenters to ovens, etc., but I’d suspect that most of that is pretty durable and so more imports won’t be needed for a while (though capital controls make would paradoxically make it almost impossible for a successful company to add capacity). Greece also exports a lot of agricultural products, but imports the farm machinery needed to make modern agriculture work.
Greece could print new drachmas until the cows came home and these industries would be unable to expand without new import to capital.