FWIW my own view is that the wreckage is probably "undiscoverable" by virtue of being either in a steep valley on the sea bed or (more probably) under a few dozen feet of seabed ooze.
That doesn't seem consistent with the wrecks and other debris found on the seabed during the search. As far as I remember, they used an AUV to check the areas the ship's sonar couldn't see into, and the shipwreck debris is still out in the open after sitting on the seabed for centuries.
Edit: of course, I guess there could be other shipwrecks in that are that we didn't see because they did sink.