There were many opportunities to intervene and prevent the incident, but the overall system of interconnected factors operated in a way that these opportunities were missed.
Translation. For 50 years, no one bothered to *actually* inspect the dam. They just phoned in the reports.
I suspect that there were a few engineers over the years who screamed bloody murder about it but it was all poopooed by the higher ups. I’ve seen stuff like that happen. Middle managers are demons from hell.