If every inhabitant gets a decent cut of the purchase price and agrees to move (or cedes large parts of the island), I see nothing wrong with it. BTW, Nauru is

If every inhabitant gets a decent cut of the purchase price and agrees to move (or cedes large parts of the island), I see nothing wrong with it. BTW, Nauru is that island nation that realized in the 1970s that it was covered with pure guano fertilizer (potassium, nitrogen, and phosphate) which was excreted by birds and bats over centuries. In the 1980s, they were easily the world's wealthiest nation, by per capita GDP, but by 1990, their guano reserves had dwindled, and most of the government's long-term investments were laughable at best. Wikipedia says their sovereign wealth fund dwindled to ~A$100M as of 2002, the government has run out of cash to fund itself (for decades now), and I think Australia subsidizes them.