This was my thinking as well that the "formal" typing instruction really helps more than people appreciate. Having a teacher come by and scold you for having lazy typing posture definitely sets a good habit. At least it wasn't as bad as the meme of a nun and a her ruler, but it was the next best thing without physical contact.

I wonder how much of this is the formal techniques like opposite-shift use and good hand/wrist posture, vs how much was from muscle tone developed from having to really push on a manual key set. Even the automatics had a bit of give to them compared to the typical computer keyboard, and now we have nearly as many keyboards on screen displays as there are physical keyboards (I'm estimating), where you may not even have a haptic vibration response on key down.

This isn't a "get off my mechanical keys" rant, this is a "should we be making exercise typewriters?" plea.