My opinion;
its 2018, if we have the technologly to go further in the ocean before, but we CHOOSE not to due to "money and time" (when has this ever been an issue for rich people/corporations? especially when it comes to possibly being the first to discover something?
dont buy that shyt at all). then they have already discovered something and are holding information from us. Its really that simple.
Keep in mind the news, government, etc report what they WANT to report. Its no different than a manager knowing about something from corporate long before they tell their employees.
If rich corporations/people are CHOOSING not to "spend money" on exploring something (and even becoming immortal in history by discovering something) then they have already discovered something (probably bad) that the public cant currently handle knowledge of.