Why would I believe that Marty Lagina wants out? Why would you believe that a 65 year old multi-millionaire with his fingers in a boatload of other pies wants to waste any more time in a "fetid swamp"? I doubt Prometheus is paying the millions for all the equipment, drilling, consultants, and other resources that are thrown at the island every year, so he's still on the hook for that. Marty's looked miserable for about 4-5 seasons now.
You are certainly entitled to your view..
But as you said yourself why would Marty do this if he was not getting a return from it. Surely you do not believe that Marty is financing this show from his own pocket and loosing money in the belief that they will find treasure and recoup their losses when they find the treasure. As you said he is a clever man.
I have not watched the last 2 seasons (with the exception of one episode) I participate here because I have always been fascinated in the history of the treasure search on OI ever since first reading of it at High School. The 200 hundred + year old search is amazing. I have done quite extensive secondary research on OI myself.
The best explanation I have seen offered for the things found on Oak Island is offered by J.Steele in her book "Oak Island Mystery solved" I can highly recommend this book if you want to see a non treasure explanation for the things found on OI.
If the Laginas were actually interested in showing the history they would of invited this lady on to explain her theory (She is a local historian that has been interested in OI for much of her life and has done extensive research on the Island).
There are many examples of the Laginas telling lies or missleading viewers in their show to suit their narrative ie finding the 90ft stone in the bookshop when it is well reported they purchased it of a person who claimed it was the stone from the bookshop. It was known about and discussed here at least one season before they went back to the bookshop (a place they had searched previously) and 'found' the stone.
When they did the pattern drilling in season 5 they showed there was nothing of value buried in the area as evidence would of shown up. They deliberately do not show maps of where they have drilled in total anymore as many of the holes they are now drilling are on top of the previously drilled smaller holes.
I do not believe anyone associated with the making of this show believes treasure is still buried on OI. It is a scripted reality TV show drama at best is my view.
Still I am not seeking to argue with you or change your mind.