If the NK Air Force is anything like my experience with the Chinese Air Force of the nineties then that airfield layout is familiar.
A line of aircraft consists of those that are flown continuously until they break. They then go on to the next ones and when they break they used bits off the first to fix them. When the bits run out they move on to the next batch. The result is that when you move along the line the first are total wrecks which may contribute a spare. They then go on to Xmas trees and eventually you will find aircraft that are being flown. After that there are new ones and as there is no hangerage they will have full cockpit covers, wing cuffs etc.
Obsolete aircraft are towed, or dragged, to another part of the airfield and will stay there for some considerable time because the airfield's fuel supplies are rationed to the number of aircraft on strength. Not withstanding this flying training usually stops around the third week in the month because they have run out of training fuel even when the pilots are averaging only eighty hours a year.
The Chinese Air Force has moved on astronomically from those days because they can now afford it. Vastly improved pay scales, equipment, training and simulators. Whether North Korea can similarly replace quantity with quality is probably doubtful.