Basic single channel DSO isn't that expensive. Training and the needed equipment is all what it takes. I remember my foreman the 80s who doesn't understand simple electronics and internal combustion engine operating theory. A parts replacer or a mechanic who does not aspire to learn or get training is going to remain a parts replacer. Technology has jumped exponentially. Nobody at repair shop level programmed PCMs in the 80s. Now, it is very common with cars since the year 2000.