Smaller Islands are notorious for having low resources and high costs, including energy, travel times, travel costs, etc, which ten to make them poor. Puerto Rico is better than a lot of islands, but some issues could not be worked around until recently. Air travel, container ships, and fiber internet connections all bring the island much closer to the mainland than it has ever been. It is now a four hour flight to New York.
The US federal government also gave them a boost, when they unfortunately passed FATCA. This prevents ordinary Americans from being able to move money offshore. But we can move it to Puerto Rico, and enjoy some of the same benefits.
I think they are committed to the right strategy, and hope they succeed at it.
Hope springs eternal!