There was so reason for the concrete to collapse until the rains weakened the surrounding land and the weight of water on the spillway. The inspections would not have found any flaw as it was out of sight and within the land itself.
Drought is a dangerous thing. It not only creates water emergencies for people, it is devastating to the land. Drought damages forests and the roots that once held the land together are damaged as well. Drought is a long term emergency and the effects of it are sometimes not known until the rains return, ie: The Oroville Dam.
Everyone is familiar with landslides and mudslides with large rain events, why would this be any different, because it is a dam and already is exposed to water? The land surrounding the dam isn't always exposed to water.
Everyone was told the proceeding Climate Crisis was not a good idea. But, the Republicans persisted and now every American life is on emergency awareness with failing infrastructure and superstorms.
California had no alternative but to release the waters to prevent a complete collapse of the dam system. It was a remarkable rescue of the people to prevent any deaths. That was all that was left to the Governor. He had no control of this event.