Their estimated cost 770million for 4.5 million sqft = 171 US$ per sq foot. seems to be at international rates.
If you compare Dubai Silicon Oasis , with very high cost of construction employing foreign labour, their approx. cost was below 150 US$ and selling price of sq ft was 177 US$ in early 2014.
It is true the prices have escalated but considering our working environment and availability of local sub contractors I think they may get some jobs done below estimated amounts after doing some changes, specially by deleting unwanted and unmatched high cost interior and exterior ideas of money wasting architects.
Dubai Silicone Oasis