Bart, when I went through electronics school they told us that tubes were here to stay, transistorized equipment was rare and that any equipment with IC (integrated circuits) would be a once in a lifetime event. That was in 1971. By 1975 tubes pretty much were on their way out, transistors were quite common, and equipment with ICs were commonplace. The instructors I had were right, but they were wrong at the same time.

Often what takes place in the field only bears a passing resemblance to what was taught.