On Reddit, a person named nautilusmaker posted this in late 2019. (NOTE: None of the quotes in this article are edited for spelling or punctuation.)
“This is a good example why seasteading on base of marine steel structures is not feasible. It was built from marine steel plating – steel needs to go to drydock and get sandblasted and then re-painted. Aditional you do ultrasound on the plating to see if it still has the required minimum thickness or if it is compromized by marine corrosion to the point where it needs to be replaced ( cut out with a torch and replaced by new, thicker plating) – well this is what you do with ships and barges. But how do you get a tower with a coral garden as ballast to a drydock to do this process ? – you simply can’t do it – so you need to close it down permanently for security reasons once the plating becomes critical (after 15 years of service life)…”
While we don’t know if this reason is 100% accurate, it is a good theory. And, in our hunt, we did find some publicity photos of the original restaurant.