In the middle and late 1960s, the sophistication of high-tech electronic systems began to grow at a phenomenal rate. Fortunately, the USAF ( and a few other nations ) had a small number of technicians - rarely exceeding 300, worldwide - who had the ability to maintain, upgrade, and even improve upon these state-of-the-art systems. Sustained, at first, by the compelling "equality" of the Vietnam draft ( a rich source of competent and intelligent recruits who otherwise would have excelled in civilian life ) the switch to an all-volunteer military resulted in a slow decline in the "quality" of personnel available for this challenging task.
They were farm boys and ghetto punks; college drop-outs and those who barely passed in high school. Scoring in the top 5 percent of the population in spatial perception, electronic/mechanical aptitude, and command of language, they were some of the best and the brightest the nation had to offer.
Eventually, basically-analog systems ( containing digital components ) were completely replaced by digital; in many cases, the software writers had no idea how the electronics worked, and never considered the hardware to be a maintainable, alignable sytem. In a binary world of on/off, there was no room for a concept other than pass/fail. Maintenance mock-ups became "test stations" in a "smart machine/dumb technician" form of maintenance - and the WCS troops were no longer required. Failing components were trashed instead of repaired ( because no one knew how anymore ), and dependence upon "spares" grew, along with depot and manufacturer-level repair. WCS troops, as a species, started to become extinct. It was the end of an era.