FWIW, most of these options revert back to default as soon as you format something; but I agree that I would have preferred iomanip to generally be a wrapper around values rather than a silent modifier of the stream.
Which is worse than none of them reverting back to default..
(...and if it makes you feel any worse, I got curious when I saw your response which ones didn't reset, and it turns out I had it backwards: most of them don't reset, except the one that does :/.)