The man was a fool. He still could have made lots of money going down 2000 or 3000 feet and mapped out shipwrecks. He might have even, over the course of his business, found unclaimed shipwrecks that had unclaimed gold.
He was an Icarius in every sense of the word.
He said he didn’t need any middle-aged honkeys working for him (who’d know their ass from a hole in the wall). Well, he showed us !
Yes, terminal case of hubris.
Some rich people are incredibly dumb.