It is endemic to the water.
In the 1970's, a dive off of Florida looked like what "the old standards" of Cayman looked like in '95.
In that same 70's time frame, Nassau and Grand Bahama were viable reef habitats, Jamaica was okay, and Cayman was still a delight. I settled on Cayman. After 1975, I returned every ten years: 1985 & 1995. That's when I stopped.
On Roatan, I know old timers there who simply do not want to look anymore. They stay on-shore. For them, it's an emotional pain.
Outflow and siltation are the killers. A reef can withstand thousands of clumsy divers without much degradation, but when development on the soil begins, when earth is displaced to run-off, when toilets are flushed.. that's the killer.
You can't know what you don't know.
On my first Cayman trip (1975 or so), I listened to the "old guys" talking how it used to be just 5 years earlier. I couldn't imagine what I was missing.
I still cant.
This is what starts so much uproar here on SB, about the condition of this place versus another... when you compare it all to what existed 20 years previous, the discussion seems rather silly and irrelevant. Which place is better? I'm on a cruise ship and I want to see the best reefs. I want a five star hotel and great diving....
Oops, too late.
The minute it becomes easy to get to, easy to stay at, and easy to dive there... the clock is ticking. Call it "getting known" if you like, but by the time the cruise ship dock is being built, it's already too late.
Money drives it all.
Then again, there is the Disney Dive. I've read here that it's spectacular.