The problem with scrum discussion is it's always compared to waterfall, particularly unyielding waterfall. Even construction planning, which is where waterfall came from, of has slips and adjustments. There were other methodologies other than waterfall before agile or scrum arrived. I went to college in the mid 90s and they taught that waterfall existed but a more iterative approach was actually used in practice. If you were doing immutable waterfall, anything would have been better, maybe including nothing at all.

Having said that, I'm glad Scrum worked for you.