Do you think that some companies want to go back to the days when a college prof and a group of kids would do all the hard work and they could deliver a product with no royalties to pay for the science, just a grant for a year or two?
Too many companies won't do the heavy lifting, look at the difference between southwest airlines, delta and american as a simple example.
Nobody makes things on islands, it's too expensive compared to the mainland.
The rich vacation there and have large expensive homes. Real estate is big, so is tourism. Some service industries exist, simply because you can't get take your house to the mainland to be painted, for example.
There's lots of entertainment for those with money. Nightclubs, yacht clubs, restarants, movie production, etc..
There's usually a very small middle class on islands. They work in the service industries that cater to the rich. They live in very meager accomidations because of high real estate prices in decent areas, and are often seasonal guest workers from the mainland who live in dorms and save money to bring home.
Most of the upper class on an island makes their money on the mainland. A few of them own local businesses. They live in heavily guarded communities.
The lower classes of islands are some of the poorest and most destitute people on Earth. They lack every basic necessity and scratch out a marginal subsistance life in slums. Lower class areas are rife with crime and violence, and many of them prey on the rich, who carry more in their wallets than some of them will make in 20 years.
So that's it. The US is the island and the 3rd World is the mainland. Sounds like fun!