Did you actually understand how those "kits" worked and how to find
which part was bad when they didn't? If I showed you a wave form,
could you identify the circuit that created it?
My dad knew and he sorta showed me at his shop, or one of his
moonlighting part-timers did (he had a couple of guys who were senior
techs at Sikorsky). I didn't say I had the knowledge of a trained
electronics tech, but I am sure I could have learned if I wanted to do
so. I did "ace" physics, calc, and chem in high school, and these were
all AP courses taught in small classes by first-rate, no-nonsense teachers.
I'm sure you had first rate teachers. Problem is you were a 3rd rate
learner.