Frankn, the answer to your question, is no. It's never over. Well, it might end the financial endeavors for awhile. But to stop the "faithful" from ever being convinced there ISN'T a certain treasure down there? Never. The only thing that lack of success shows the faithful is that ..... doh ...... it must be deeper! See how deeply the human mind wants to believe? Why do you think Tnet has all those subsections on the various legends and superstitious lore on the myriads of supposed treasures out there? Why do you think the goofy stories in all the old treasure magazines of the 1970s sold so many editions? It's the psychology we all have ingrained in us to believe "lest we be left out". And no amount of counter-evidence convinces them otherwise.
When I was hunting all over Mexico, I came to one village with my host. A certain boy in his young teens ...... who found out that some americans in town had metal detectors, came to me asking to go check a certain cave. I followed him out into the canyons near town, to a cave. It went in a certain short distance, and opened up into a room sized cavity. I turned on the detector, and heard nothing. Scanned the entire floor. Switched to all metal, still nothing. As I turned to tell him, I could tell he was in dis-belief. So I removed my headphone jack and let him hear for himself. He still couldn't believe it, and said that what we needed was a a) machine that goes deeper, and b) a machine that finds only gold. And thus he started asking about other type detectors made in america. He was convinced there was a treasure there, because he'd seen sparkles in the ground, or smoke coming from the hills, or had a vision, or some such nonsense.
I saw this same scenario, with different twists and tales, all over mexico. It was never that a treasure wasn't there, or that there 10th hand stories passed around for 5 generations wasn't iron-clad fact and true, it was always that the treasure was deeper.
So too is it with this oak island thing.