The irony is that, apart from representation in Congress, Puerto Rico’s current status is great for its citizens. Lots of US government benefits without the same tax burden. Its a testimony to how badly the politicians in Puerto Rico screwed everything up over the past 20 or 30 years for them to be in the position they are in now. They had it made and still screwed it up. Both becoming a state and independence will result in a lot of pain for the Commonwealth.
https://en.m.wikipedia.org/wiki/Puerto_Rican_government-debt_crisis#Cessation_of_federal_subsidies
For much of the 20th century Puerto Rico was subject to favorable tax laws from the US federal government, which essentially acted to subsidize the island's economy. In 1996, US President Bill Clinton signed legislation phasing out important parts of the favorable federal tax code over a ten-year period ending in 2006. The end of the subsidies led to companies fleeing the island which itself subsequently led to tax shortfalls. At first, the Puerto Rican government tried to make up for the shortfall by issuing bonds. The government was able to issue an unusually large number of bonds, due to dubious underwriting from financial institutions such as Spain's Santander Bank, UBS, and Citigroup. Eventually the debt burden became so great that the island was unable to pay interest on the bonds it had issued.
It's not like they're blameless, but the problem started with Clinton and Congress.