"Very few people anymore realize the amount of info on a framing square."
Yup. You just don't see them in use as much anymore. Now, I'm not an old-fashioned guy, and I'm as likely to pick up a calculator to figure something out as I am to do anything else. But a framing square is worth learning. An amazing tool, developed to make life simpler for the guy with the hammer and saw.
I learned it just because I wondered what all that stuff was about on the square. They had this little book at the lumber yard, so I got a copy. Amazing!
Do apprentices still learn how to use it? I have no idea, since I've never worked in the trade.
I doubt many people learn it anymore. Nowadays "rafters" are seldom cut, having been replaced by stamped together trusses. My Dad could cut every hip, jack and common rafter for a house just by knowing its' dimensions. They would be stacked up and ready for the guys to nail on. Never a measurement taken up on the roof. Vanishing breed I'm afraid.
My husband and I were helping friends build a deck. They had a construction worker there to do the cutting and measuring, we were the nail pounders. When we left I remarked to my husband that I would love to have a speed square like they were using, just seemed so useful. Guess what my anniversary present was that year? A compound miter saw and a speed square.