I was just thinking...
Dharma was set up to save the world.
It focuses on unraveling a set of numbers using the most advanced and involved science known to man.
The DI has been trying to pull as many qualified people onto the island as possible.
Fate vs. Free Will -- we've seen that fate consistently wins out in the end.
Could it be possible that the whole point of Dharma is not to save the ENTIRE world, or even the whole human race, but instead just ensure the survival of the species? Suddenly the Island becomes a bastion of the best and brightest of humanity, preserving all the scientific knowledge it has.
Once the date determined by the Valenzetti equation arrives and everyone of-island dies, Dharma releases everyone to rebuild.
Could this possibly explain the hints toward ancient civilizations having built facilities that Dharma built over (with access to some really neat toys -- the smoke monster, the swan site, the temple), and the arrival of the Black Rock crew?
just a thought.