It's more patients vs resources than developed vs undeveloped, it's much easier to handle 91 cases at once than 900 or 9000. Italy is also a developed country and the mortality is around ~3% so far in Italy, Japan is developed and it's at ~1.5%. At the moment it seems like Korea is the biggest outlier with mortality under 1% but also with a lot of cases.

I'd rather be in a developed nation, but you're cherry picking your example.