That is apparently an issue of design and may be site specific.Have you seen what the occasional rogue waves do to the shore? Up near Lighthouse Point there USED TO BE 2 very large artificial rock reefs jutting out about 20-30 feet from shore. We have dived that area frequently for 25 years. The rocks were big, damn big. They are mostly gone now.
This is Bonaire. IF you could convince them to put anything in (doubtful), I'm pretty sure it would not stand the test of time and weather.