I joined up in 75 as a Rigga Mech, and one of the first things I had to do, on arrival at Tern Hill, was my Promotion exams (plural) LAC to SAC.
Safety Demonstration: Showing my Sgt around the hangar fire and first aid points.
Practical: doing a metal bashing test Job to LAC level (Shoite) and
Written: Doing a vote for Joe exam on techie things.
Many Moons later I did the JT/Cpl Promex at Honington - Mentored by a Chief in deeper Techie stuff and again doing Vote for Joe's...but no practical work. My Aptitude Assessment was signed off by lending my Chief a new Phil Collins Album..No Jacket Required. I was still on Time Promotion up to the point I got promoted to JT and I was on Stn Duty Dog at LBH on the day I should have been promoted to Cpl. - although I was promoted some months later.
Later still, doing the SNCO Team Building stuff at Hereford and Scampton (where the only useful thing I found was learning how to guide a crane properly!)
So yes, the dumbing down of us techies was pretty continual...For me, it picked up as soon as I left the RAF and started learning about all the other things that surround helicopters and aeroplanes! - And I'm still learning.