Boats can be recovered. That might make someone sweat if it is determined exactly how the boat sank. Boats get scuttled occasionally by people who would rather have the insurance money
than the boat.
A boat that size would be compartmentized with a minimum of four or five watertight transverse bulkheads, if it was designed properly. Chances are good it would also have been built to a classification societies standards, like ABS or Lloyd's Register for example. Most mega-yachts are built to one or another classification societies standards. All of these organizations have standards for compartmentization. Meeting one of the classification societies standards keeps insurance
One of the classifications for ships is how many compartments can be flooded before the vessel is too unstable to be considered safe. They are called one compartment ships, or two compartment ships, etc. This of course also varies with how much cargo they are carrying and the metacentric height.
I am not saying it was scuttled, but I would not rule
out the possibility either.