A tropical island thought experiment

Here's a little thought experiment. Daniel Defoe's Robinson Crusoe, published in 1719, caught the imagination of the world and (according to Wikipedia) had more editions, translations and imitations than any other work of fiction through the end of the 19th century. The individual was shipwrecked alone on a desert island where money and society were useless. It is the vision of the independent individual, and in some ways was a precursor of enlightenment thinking. It was also often used as a metaphor in economics.

We've also had other tropical island shipwreck stories in the culture. Lord of the Flies is one (which I haven't actually read.). Recently, there was Lost, which is a story of mysterious forces and hostile opponents. There were various iterations of Survivor.

Here's a different updated tropical island story, motivated by spending some time on one just recently. Let's call it Mai Tai. 

There are plenty of remote Pacific islands with runways left over from the second world war. A transpacific flight has engine trouble, and loses altitude. The radio is knocked out. Just as a water landing in mid-ocean looks inevitable, the pilot spots an island, and even better, a runway. 

The plane comes to a halt and the door opens. Two hundred people slide down the chute onto the island of Mai Tai.  The beach is beautiful, the palm trees sway in the soft breeze, and visible just where the forest begins is a sign saying "beach bar this way". 

There's a sign beside the runway, however, in English, French and Chinese. "Quarantine zone", it says.  The runway was built to serve an experimental biological station back in the war years, and the lab leaked.  No-one can leave the island for at least a year, and even after that only two people can be properly decontaminated each year and leave the island. 

There are beautiful houses for all the castaways nearby on paths through the jungle. Supplies will be delivered regularly. Delicious food will be available.

All production of necessities will be taken care of. There is enough food, shelter, water, and wine. It's an endless tropical holiday. No payment will be demanded, and there is no set time limit. Every year you can choose to leave the island, but you can't return. And you can send one letter a year to anyone you like in the outside world.

How long will people stay? What will happen? Will people decline into aimless boredom, or arrange things into paradise?

The essence of this is of course all material necessities are taken care of. What then? That is the choice we are going to face.