One track
I appreciate what you are saying above with one caveat!! For any search to be carried out at such considerable depth the searchers have to be pretty confident that the wreckage is in the confines of quite a small area.
Even with that certainty it will be like finding a needle in a haystack.
There is still no evidence that this relatively small area holds the wreckage.
If this is a clutching at straws location which looks more and more likely then the game is over.
Frankly a politician saying we need to regroup, reconsider or whatever is a pre warning that they have run out of reasonable options and a withdrawal is likely