Here's another puzzling question. If with the honey comb shape, we can have the most inner space with the least material, why do we continue to build retangular houses?
Non-rectangular houses save neither labor nor material in today's market.
Currently, the cost of labor accounts for roughly two-thirds of the total cost of building. Building corners of any kind is far more labor-intensive than building a straight wall.
Also remember that common residential construction materials are universally made and sold in standardized rectangular shapes.
Houses with non-rectangular shapes can cause problems with furniture placement. Often the proper solution is to provide built-in furniture, but some homeowners don't like that (I like built-ins, but we're talking about the whole market).
Finally, wouldn't a spherical house provide the most cubic footage for the least amount of material? Again, this is useless as a housing concept (people try to build things like this today, but they don't work too well).
This situation (for residential architecture) could change with new materials and construction methods.