The area in which the supposed "Wheel of Fortune" was sighted was in knee deep water. Since Dr. Stone (adult male) could not pull the wheel out of the water it must have been anchored pretty well by something, either more metal or hardened sediment. Maybe it was/is anchored well enough to resist having been moved by the next storm and rests under a layer of sand, easy to miss during a visual walk-through survey.
Even if its position changed, it might only have been moved farther into the lagoon a bit. At this point it might be interesting to research this area with a surface towed marine magnetometer. Compared to the costs of the ROV this unit is a bargain and can be pulled by a person, keeping in mind that the person towing it should have no metal on them during the process.
This object would be a positive identifying part of the Earhart plane and should possibly be looked for again.