I grew up playing classical music. Discipline was the fundamental long term value that parents and teachers sought via this method. At that time, discipline was primarily the path apart from boredom and simple alternatives that were forms of junk-food-like entertainment (afternoon TV was the big one).
Today’s discipline is entirely weighted toward focus. Focus, not against backdrop of boredom. Instead, it’s against a backdrop of near constant stimulation and options.
It was far easier for me to choose a path away from boredom. I do not envy kids these days.