Possibilities, possibilities ..... Anything is possible!
For a retiree, likely these are major concerns that could occur or that are already occurring to some degree or another:
1) Doctors leaving the Island, new doctors just out of school looking to get better pay and learning from others.
2) Taxes going thru the roof in order to pay debt
Number 1 is already happening, but I think enough will remain, bigger problem with Specialist. While some will remain, some will leave, you can hedge the exit of the Specialists by using a health plan that covers you in the mainland, Florida is 2 hours away, NY & Boston about 4 hours away, a little more than trying to drive to San Juan. As to regular doctors .... Just need to wait a little longer. Quality of Medical will not really suffer, but availability and easy access yes.
Number 2, Governments always have a excuse to raise taxes but the ability of the common folks to pay it is not that great. The average Puerto Rican will be affected the most, but take solace that there are a lot others in worse shape than you. Taxes can only go up to a point after that it creates trouble for the government as the people will raise hell.
Quality and repair of roads has always been an issue, Electricity cost - get solar, water put a cistern or a well, food prices - plant more food and raise chickens.
Only #1 above is somewhat of a concern to me. But I am still moving in.