FWIW, it cost me 2100$ USD for 8 nights / 9 days for a condo in Grand Cayman, car included.
Add 300$ for insurance (my Canadian insurance co or credit card co does not cover me there)
Add 290$ for 3 boat dives
Add 12$ for tank rentals in the North part / turtle reef area
Add 50$ per person for food per day
Being able to relax in a land-locked bed every night - priceless !
A better comparison would be staying at a land-based AI diver resort like at Ocean Frontiers, that have a beach and great diving, compared to Sunset House with no beach.
Or some other similar AI dive resort in the Carribean.
IOW, what's the advantage? I see one with a live-aboard in Taiwan, or Galapagos, where it would just too much time boating from dock to dive point every time, with the dive sites in mostly remote locations.
But the Carribeans? Just go where the wind is at your back, walk in and dive. Like around Little Cayman, that I'm sure I would have liked better than Grand Cayman - for the diving.