It is hard to tell if Puerto Rico's problems are a result of failures of the U.S. Government or the Puerto Rican government. Congress has not acted on statehood and Puerto Rico has not requested statehood. Sure there were referendums and huge majority of voters, voted for statehood, but the people actually voted, represented less than 1/4 of the eligible voters.
In the meantime, Puerto Rico's population has declined nearly 20% over the past 20 years. The brightest and smartest have been leaving, decimating any future hope, imo. Puerto Rico appears destined to remain an unincorporated territory.