With a very tall tower, you can't let any of the space until the whole building is finished. A more modest collection of low rises is quicker to build and can be let bit by bit. Building high goes beyond making money. It taps into the the most primordial of architectural impulses - to impress. In the end, building is not necessarily a rational, calculating process.
Nobody is immune.
The new cities of the exploding Pacific Rim are all building high. The twin towers of Malaysia's Petronas building, a witness to Prime Minister Mahattir's edifice complex, are taller than anything else in the world, for the simple reason that they are regarded as a national virility symbol. Mahattir deliberately set out to top the Sears tower in Chicago, the city that gave birth to the skyscraper in the first place. Chicago has been stung enough by Malaysia's presumption to build something even taller than their Sears tower, for two decades the tallest building in the world. Under the innocent sounding name of Seven South Dearborn, the Skidmore Owings and Merrill practice has designed a needle-shaped structure that will retake the title of tallest tower.