BS. We had overhead projectors and transparencies, and meetings were even longer and more tedious, adding in the time for the presenter to position each slide on the screen. I attended a seminar by graphic expert Edward Tufte back in the 80's - he stated that the standard business overhead slide was the lowest form of communication known to man in terms of information per unit. His book "The Visual Display of Quantitative Information" is still the best resource to learn about conveying information graphically. PowerPoint is better.....but please don't stand there and read your PowerPoint slides in a monotone. May as well have used an overhead.
Prior to overhead projectors, they just passed out little handbooks. There was a time when those in the meeting were expected to take notes. Of course, it was common to use one’s own brain back in those days.