There are people (notably, Ha-Joon Chang) that have claimed that those protectionist policies have made South Korea more competitive, but I think you'd find a lot of economists disagree with that, and that South Korea become competitive in spite of those restrictions.

Keep in mind North Korea has had even stricter trade restrictions, and they don't have any functioning modern industry at all. Trade restrictions reduce export market size, insulate companies from competitive pressures, and those problems only serve to reduce capability, not increase it. Maybe there is some sort of happy medium of protectionist policies, but I've never seen any sort of framework for understanding how you could derive where that happy medium lies.

If trade restrictions only ever made countries more competitive, we wouldn't use them as a punishment.