Is it possible that some of these monster homes may actually turn into senior care homes?  If they are indeed for family, then this is a symptom of the housing shortage in Hawaii.  New homes are not being built fast enough, and existing homes are not affordable.  So, the only way to go is expand your present home.  Now of course, 28 bedrooms is a bit much so I'm going to say that it is not likely family, but certainly homes with 7-8 bedrooms are a possibility for multi-generational families.