Maybe I can help you out here.
Prior to SMS when we had a regulatory inspection, they were inspecting to a standard. Keep in mind that at airports our infrastructure is static: concrete, asphalt, steel, and glass. An inspector would come in and ensure that the paint lines were correct, the runway lights were working, things of that nature, just to oversimplify it, even though I assured them that we didn't change the runway or anything else like that in the last little while.
What we had predating SMS was to a set standard, a very prescriptive, standardized sort of checklist inspection. Fast-forward it to where we are today and we're actually looking at the tangible safety results and things that can be measured.