I'd like to think the right managers and authorities will do the right thing in such situations. But empirically, they didn't.

Perhaps it's a specific failing of the Japanese governance regime, and knowing their own affairs more than we do, they don't have sufficient confidence they can fix that failing before another 'freak' event occurs.

Had it been a gas plant or whatever, it wouldn't have mattered. But it was a nuclear plant, and in a nuclear plant any improbable event like that is a major f* up. That's the core issue.