First of all, there are a lot of people willing to die for their country as it is. As soon as people are willing to give up their lives, you're not changing shit. These people didn't grow up like you and me.
Secondly, there is a world of difference between stepping in and stepping in. One of the main reasons that North Korea is so isolated is because of sanctions. That is also a form of stepping in.
Thirdly, we already saw war and foreign meddling in that area. That's exactly why America is the great evil opponent of North Korea. That's not a coincidence or just because Kim Il Sung, Kim Jung Il or Kim Jung Un hated "freedom".
Now you ask, what other solution is there?!
Well, a lot of people are actually working on that. By launching information campaigns and spreading Western/foreign music into the country. Real change comes from within. But please remember that this country is now lead by the third generation of absolute leader.
A co worker asked my partner if she could knit her a sweater like the one she was wearing. She wore a gorgeous, fitted, bespoke sweater she made herself. She quoted her 1200 euro. Needless to say, she didnt get the commission.