It really is a big pity that Carnival pulled out of San Juan after decades sailing from the port. Such a great itinerary too, even if it hardly changed. I do remember the PR government starting to make things a little difficult for cruise lines around the time with some lines going to seasonal only (before Carnival announced exiting). I THINK it was raising port fees among other things. On top of that was Carnival had to work quite a bit to fill the ships with locals at times and after Irma/Maria, many Puerto Ricans were not in a place to take a cruise vacation. Most continental US guests were not as fond of the longer flights to SJ as well. They tried enticing mostly British guests with embarkation in Barbados, but still numbers weren't too strong. This is how eventually Liberty was moved to TX for increased demand and Fascination was sent to SJ. The final and biggest piece that ended SJ service was the need for Fascination to replace Fantasy. All other ships and ports were strong enough not to pull a ship from for SJ, even seasonally.
I've done the Southern itinerary from San Juan 4 times and loved it. It would be awesome to sail it again, but I'm not counting on it with Carnival for the foreseeable future. I'm not placing bets on Sunshine moving there.