I didn't say "salvaged", I said "looted". Operating in secret gives you time to strip and run, not to do real salvage. Archaeology will lose big. Gee thanks, lawyers!
Even “looting” a major deep water wreck would involve too many complicated logistical modalities. It couldn’t be researched, found, and looted in total secrecy. It would be like trying to gear up for a moon shot in secret.