Regardless how rich the country is, with this war it will be doomed for good. No one even wants to invest in s korea now because of the tension and if war starts, it will take another 20 years for the country to be out of stone age. U.S has directly stated it will intervene  and shipped the war heads and there's a permanent huge military base just like in every country. 

Again i don think n korea is scared of US , they are well aware they will get involved but also they know they are nuclear power so that will try to back off as much as they can. Apparently that is the only way for other small countries not get bullied. 

Regardless if this war starts it will be a BIG mess, china did sent troops when the tension started few months ago, which ofcourse they deny, iran will get involved....a war with few ak47 and stones has been going on for more than a decade and its worse now just imaging how long this is go....

And most of the plp who like to talk big about these wars will never  go to the war rather eat a burger and watch it on yoututbe lol..talk is cheap