Would OA-cities be affordable or would they be destined to become the ultimate form of “gated communities” for the wealthy?

Could an ordinary citizen afford to live in OA-City?

Most people would probably assume that an exotic building like Deltapolis would be much more costly to build than a conventional high-rise apartment block, and thus the rents would be unaffordable for Joe and June.   This may well be the case initially due to the laws of supply-and-demand – but also because pyramids are so rarely built there will be a “learning-curve” to overcome.  The only large “residential” pyramid ever built – as far back as 1993 – is the Luxor Hotel in Las Vegas.   Prototypes are always far more costly than production models, but once their construction techniques become familiar, I would expect pyramids to be more economical with materials than their conventional vertical-walled equivalents.   

A unique building which went way over budget, largely due to the engineering challenges of its unusual (and never to be repeated) shape.  

Learning from experience

Any unfamiliar-shaped building – such as a pyramid – will present more technical problems than conventional vertical walls.  An extreme example which best illustrates this is the shell-shaped Sydney Opera House, whose construction began in 1959.  Having soon exceeded its original budget several times over, the NSW state government launched a popular “Opera House Lottery”, the proceeds of which went to finance its eventual completion in 1973.

Had the SOH contractors  gone on to build more shell-shaped buildings they wouldn’t have faced the same problems since they would have learned from their experience with their first (and only) attempt.    Subsequent shell-roofed buildings would have been much cheaper to build than the original.   But there will probably NEVER be another building like the SOH because the design is totally impractical and was selected – by public vote – over conventional designs because a flamboyant building would “put Sydney on the map”, and in that it was a huge success.

Pyramids are the optimum shape for very large buildings

Composed of triangles leaning against and supporting each other, the structural integrity of a pyramid is superior to all other buildings.   Because its weight is distributed over a large base, a pyramid would presumably need shallower foundations than vertical walled buildings and its skeleton might require less structural steel (or perhaps even timber..?).  So, if or when large Pyramidal buildings become as commonplace as they surely deserve to be, their construction cost might well be significantly less than conventional vertical-walled buildings.  

REASONS WHY PYRAMIDS MAY BE CHEAPER TO BUILD

• OA-Cities will evolve easily-replicated standardised design templates.
• Modular pre-fab construction techniques – floors and walls, even complete apartments, could be simply slotted into a skeletal framework made of steel or even “ENGINEERED TIMBER” 
• Enormously simplified SERVICES and UTILITIES infrastructure.
• No service roads 
• Land cost (per dwelling unit) reduced by up to 90%.
• VOLUNTEER LABOUR provided by citizens-to-be, in return for future rent credit.  Even unskilled labourers could lend a hand as most jobs on building sites don’t require specialist skills.