As a native, I don't think I can give you a nuanced answer on Roosevelt Roads on here without getting the ban hammer. Wiki does a nominal job of describing the chronology, if you're so inclined. All I can do is to parrot the US Navy Congressional answer back then, which was that if they couldn't bomb Vieques they were gonna take their ball and go home. And so they did. To be clear, this is not a topic unique to PR. States like LA, OK deal with industries that employ people in capacities that compromise the health of the very communities they dwell on. I call it hostage economics. Aaaaand I digress.....
As to the suggestion of transferring the Gitmo mission into a US territory, I again I cannot give you a nuanced answer on here.
PM me if you want to know the not-for-mainlander consumption answer to the history of the questions you pose.