Take a walk forward from the days of paper tape and punched cards through to today and learn there is a method to the madness. AGILE is just the latest name for "hacking on the fly" and guess what? There have been a lot of different names for it over the decades.
True Software Engineering uses SDLC Waterfall. The methodology didn't just fall out of the sky. The greatest minds of the time focused on creating success the first time rather than failing as fast and as often as possible sprint after sprint.
There is a "why" behind everything in IT history. Take time to understand the "why" and you will never champion AGILE again.