He has replaced the most progressive military officials with loyalists, and songun policies make sure the army is happy. I can't really see why they'd ever want to revolt. In a democratic korea they'd be much worse off, plus many would lose their jobs due to a large army no longer being necessary since the US wouldn't be a threat.

I don't think that a military first policy where most of the country's resources are devoted to the military at the expense of millions of civilians would necessarily make the army happy.

Meh, idk, they were happy to support the regime when Kim Il Sung died in the 90s and the people were starving and resorting to eating grass, leaves and soil to survive. Nowadays the people aren't that bad off for korean standards... they have their basic needs covered for the most part, and they seem satisfied with what they have. Obviously that's mostly because they are ignorant about the majority of things that happen outside the country, but regardless they also seem to be uninterested in demanding change. All of the former communist countries had some sort of underground resistance movement that the secret police would chase... in NK there is none and the secret police pretty much only has to deal with the occasional "rotten apple". Their main focus is hunting smugglers that bring in korean dramas and such from SK (aka people wanting cash, not freedom or civil rights for the country).

I think the whole country's mentality would have to change, before the military starts feeling guilty. Keep in mind that they are brainwashed to believe that the military must come first, because after their awful experiences from previous invasions (WWII, Korean War) this is something the people are very afraid of. I'm sure that this whole communist shit show will end eventually, but I don't think it's going to happen soon or with a coup against the current leader. I hope I'm wrong ofc, but I just can't be optimistic about this.

Kim Jong Il was a more popular figure than Kim Jong Un though, and this was before the internet when NK was a lot more isolated. The people are brainwashed to some extent but they are very aware of other countries being more advanced and not suffering from mass homelessness and poverty as they're told. Communism has been dying in NK ever since the famine, there are an abudance of sole traders now. I'm pretty optimistic things are going to change for the better there in the next 20 years.