Let's look at a Google Earth image of Paris from 50,000 feet up:
Now lets's look at Manhattan from the same height:
Notice how at this scale you can see the minor streets of Manhattan pretty clearly, but not the minor streets of Paris? Paris actually uses its land very efficiently--it does not waste space on streets or setbacks. As a consequence, while it can be livable (if not affordable) with 3/4 of the denisity of Manhattan and a small fraction of the number of tall buildings of Manhattan.
There is no question that Ed is correct that mega-cities such as Mumbai, Cairo, Mexico City and Sao [Paulo] require skyscrapers to house people adequately and affordably. But as he also notes, building skyscrapers is a lot more expensive than low-rise buildings. For many cities, more efficient land-use could go a long way toward making cities more livable, more walkable, and less expensive.