Common sense, business sense. Starting a massive treasure hunt, spending millions of $, involving tons of other people, 3rd party companies, scientists, archaeologists and historians without having some evidence, some conclusion to at least support the belief that there is something buried there, would be stupid and backwards IMO.
There have been countless scientists & historians over the years, from around the world, that have chimed in with specific information they're privy to, that supports the belief that there is or was something of immense importance buried at Oak Island.
Although the History channel is now contributing $ to the production of the show, in the beginning, Rick & Marti were funding the hunt out of their own pockets, and they still fund a large portion. The History channel pays for the production costs, the Lagina's pay for other necessary expenses such as the cost of drilling, ultra-sound testing, scientific analysis of metals and wood, etc. Watch the early episodes, Marti was always concerned about how much they were spending, he watched every $ like a hawk. The last few years, he hasn't shown the same concern, probably due to the History channel kicking in and taking 1/2 the load off his shoulders.
But to just pick a piece of land or island and say "let's dig" & spend millions of $, without having any historical evidence, clues or documentation to at least provide a reasonable belief that there's something there would be totally ludicrous. There may be something there, or maybe not, I don't know. But as I see it, there's 3 possible outcomes. 1. They find treasure. 2. They find evidence that there previously was treasure. 3. They find nothing and give up.
But I do know that if you're going to start a massive and expensive treasure hunt, and you'll need to line up investors, a large crew, scientists, various experts, 3rd party companies, and get the History channel to sign on and commit to spending large sums of $, you're going to need to show them something more solid than just telling them that you have a "feeling" or had a dream that there's something there.