There is something so curious to see that amount of energy going into a project like this. But I am reminded to 'follow-the-money' and see who is really invested in the search. I am sure History Channel is invested, but not necassarily because of any treasure, but to create unscripted programming that sells big advertising space. Some of the folks on the show appear to essentially be employees of the Oak Island Tours Inc (name?) and that company uses various sources of income to fund search operations. I am sure its a fun job for a few of those folks (and like any job, they get paid for their efforts), and the idea of sharing in the treasure $$ is their long-shot upside). And the construction companies are all just doing their jobs, and selling Oak Island Tours Inc the products or services needed. For a few people on the show, its an actual passion regardless of the money (I am sure Marty, Rick and Dave have the passion and would follow the dream regardless of $$). And it doesn't hurt that Marty owns a very successful winery in Michigan, and I think has part ownership of an industrial power company too... allows him the freedom and funds to chase his dream.
Every one of the companies like Oak Island Tours Inc that have tried this search for 250 years are chasing after that 1-in-a-million chance that there is some truth to the story. That said, most of what is being 'discovered' is the debris of previous searching efforts, or the artifacts of people that have spent time living/camping/wandering across the tiny island itself. They have proven that people have walked those acres for hundreds of years, but the land deed map already shows that, so no real surprise. They have found a couple of bobby-dazzlers laying on the ground, but easy to see that occur with people there (thats why metal detector people comb beach fronts every monday morning around the world today). And the timbers and excavation evidence is clearly left by the previous search efforts. The existance of that stuff just confirms that others have heard the same fanciful story and tried to chase it. And the amazing lead cross is evidence of previous wanderers on the island, not evidence of any treasure being buried. And finally, the swamp appears to be, well a swamp which was probably the space between two islands that filled in with sediment over the 250 years. Again, no mystery there. (Do you know they still find ships buried under the streets of San Francisco?)
All that said, I also watch every episode. It's like driving by a car crash... you just got to see what's happening.