What is your take, on the decline of our Military presence, around Puerto Rico, and the Virgin Islands, over the past 40 years?

From the naval perspective, once Vieques was closed (upon the urging of people who didn't rely on the Navy for their livelihood and who didn't even live on the island) NS Roosevelt Roads was destined to close. We still do have ships in 4th Fleet conducting CD OPS with the USCG and C4F still is conducting Southern Partnership cruises to Central and South America.
Personally, I loved Rosie Roads. It was a great base with great facilities and beaches. Don's Lighthouse was always a great place to grab a cocktail.

I would spend at least three weeks a year in Puerto Rico flying missions out of Muniz and no they are slim to none. I miss those days.

I was stationed at Fort Buchanan Puerto Rico for the last three years. If you have some free time Google the battle of Vieques. Essentially a vocal anti-U.S. minority (the Green Party) under the guise of environmentalism lobbied to get the Navy to give up the training area on the island of Vieques. Without the Vieques training center it was not viable for the Navy to maintain a presence in the Caribbean. So along with the Vieques training center The Navy also closed Roosevelt roads the then largest military installation in the Caribbean. There is still a fairly large reserve force in the Caribbean The first mission support command.