In my opinion, the problem was from a combination of all of the above. My SNCO who retired as a crew chief said many of the problems started when MX got severely cut post BRAC. Much of the experience was gone and the work fell on the shoulders of the younger NCOs. This they did not train the young airmen like they were trained. As everyone progressed, the lost knowledge stayed lost and only got worse. The planes got older, parts more scarce and the demand increased. On top of that, Big Blue decided that there were too many specialties, like in avionics. 3 different specialties became one. It worked at the time because the guys had some cross training and experience. The new guys did not. Also, a crew chief is a crew chief and can work on any bird. So they pulled a lot of ‘excess’ crew chiefs and sent them to different jets. Ive seen a C-5 guy in charge of the flight line with A-10 and F-15 crew chiefs working on F-16s. You can imagine how well that was going. They’d work the crew something like 26+ days a month to try and get working aircraft CONUS.
When ops and Mx split, I think many of the Mx officers went full shoe clerk. Chasing green slides rather than actual success. Their drive for future rank through successful PowerPoint slides probably led to many of the current toxic cultures in Mx. My old SNCO would smile about the old Ops+Mx days and tried to hide in my shop as long as he could.