Thousands perished from last year’s hurricanes, and many more struggle to survive amid wrecked, impoverished lives. But for one class of residents, it’s canapés and bubbly all around: The not-quite-ultrarich have flocked to the U.S. territory since its 2012 law offering a tax haven to mainlanders. The catch? Establishing bona fide residency by severing all onshore ties. Although meant to spur development, the act has been stripped of key provisions, such as requiring transplants to buy property and hire local workers, leaving doubts that it will help the island’s economy.