Like the Titanic stuff, it is primarily a catalyst for an emotional connection with the past. Whether or not to disturb a wreck is usually decided by economic rather than ethical factors. Consequently, we're not much inclined to consider ROVs to search where we think the airplane probably ain't. For comparison, just imagine that someone MAY have dropped a mobile home somewhere in Yosemite National Park. This past summer, Dr. Ballard spent a month or more criss-crossing the site of the Battle of Midway.
Stuff is hard to find.
And as Dr. Ballard has repeatedly demonstrated, it's hard to find stuff that isn't even lost in the first place. As an aside, Jack Grimm came within one-half mile of locating Titanic. I'm not sure how long it would take to search that much ocean bottom, but I'd suggest that you pack a lunch. This gets to the heart of some very basic historic preservation issues. I'd be very interested to hear some opinions on this from some of our trained preservationists on the forum.