Will reunification costs reach 10 quadrillion won? Looking at investments in the US

‌With 500 trillion won invested in the US,
building thermal power complexes, 8 nuclear power plants, and Alaska LNG facilities,
I'm starting to think that if reunification happens, building infrastructure in North Korea might not actually cost as much as 10 quadrillion won.
It's not like we're going to develop every single rural area in North Korea.
They say the Gadeokdo New Airport can be built for 10 trillion won,
and that's for an airport built by cutting through mountains and reclaiming land.
Incheon Airport cost about 19 trillion won cumulatively up to Phase 4,
and the cumulative cost up to Phase 5 is expected to be around 25 trillion won.