Kiln-dried wood must not be used; the lignin in the wood has been permanently set during the hot dry kilning process. No amount of steaming or soaking will weeken the lignum bond sufficienntly for sucessful bending. The same applies for air dried wood that has been allowed to dry and stabilize below 10% moisture content.
I wouldn't go that far. Kilned wood is steambent successfully every day. Higher failure rates, but hardly impossible.
““Perhaps then, you will say, ‘But where can one have a boat like that built today?’ And I will tell you that there are still some honest men who can sharpen a saw, plane, or adze...men (who) live and work in out of the way places, but that is lucky, for they can acquire materials for one third of city prices. Best, some of these gentlemen’s boatshops are in places where nothing but the occasional honk of a wild goose will distract them from their work.” -- L Francis Herreshoff