Logistics
This plan does not show how the logistics would work for the inhabitants. If the entire "island nation" consists of millionares then how do they plan to provide enough food and water for everyone? What would the population capacity be for such a group? Then there are the problems associated with weathering, wear and tear on the infrastructure. This sounds like a possible solution to lack of land area for the ever growing population of people, but it also sounds like "Water World" with the dysfunctions apparent in the movie.