I'm sure every major exchange has contingency plans to operate out of a backup location. I'm not aware of any single point of failure in banking, oil, or cargo, and if there were, mundane threats like weather would far outweigh terrorism anyway.

Singapore is a major point of failure in banking, oil and cargo.

But can't be taken out by a simple bomb, not even remotely close.

I think we disagree on what "crippled" means. You have taken it to mean "no longer functions or exists", which I think many handicapable people would disagree with. It simply means that it operates at a measurably diminished capacity in some regard, which with the economy can have profound implications.

If the NYSE building were bombed on an operating day, it would absolutely have dramatic financial repercussions, and that market would absolutely be crippled. Would some simile reappear? Of course it would, just as government would reappear if a full capital building were attacked. But the impact would be major and it would be felt.

If the traders could be rational enough to pick up and move to new temporary offices a few blocks over and carry on with their business the next day, the consequences of a NYSE bombing would not be so dire. The dramatic financial repercussions you mention would certainly happen, but only because people would panic.