Also worked a contract (7 months) on a cruise ship, acupuncturist. Was offered a chance to extend, or change to the music department, no thanks.
I can verify that a lot of people were living long term on the ship. HAL, so we had an older clientele- average age something like 60-85. I had some patients who had been on the ship for a few months, they would switch ships every so often just to change things up. Knew some who weren't my patients who had been on there over a year.
The medical team was better than I expected. We had our own little pandemic scare with the flu, with staff mandatory vaccinations up until herd immunity was reached, and we were denied entry into 3 small Pacific island nations, ending up at sea at one point for 8 days. Held together ok. I ended up getting a lot of patients then since the wait for the Western medical team was long, or the meds weren't effective for them/they didn't want to take. That being said I would never ever ever want to cruise myself.
But I can see the appeal for some and many long term care facilities in the US are pretty terrible . It's just when SHTF that things can skyrocket in a super bad way.