A lot of internet slop answers are wrong. Korea did not have free market policies until mid 90s. Government picked the winners, gave preferable loans, negotiated with Japan and US, thought hard about key industries to back (steel, chemical, electronics later), sent soldiers and workers overseas, stabilized rice prices with a single national agricultural cooperative, gave resource for rural development based on performance, developed national arms industry, went to middle east for infrastructure deals, etc. So many to list.

If you open third world market to world market, it either gets trapped in middle income trap (failed to move up value chain) or gets dumped with imports. Neither “shock therapy” nor “de-nationalization” work in all cases because those two rely on either competent or benevolent leadership, and elite that is willing to pull together rather than loot and flee.