No, the reason this hasn't happened is because of barriers to
trade and migration imposed by national governments. If each
person on the planet had an global market for their stuff, and
if laborers were allowed to travel to and work in the most
lucrative markets without first securing permits and passes,
then we'd see a very drastic increase in the global standard of
living.
Of course, some of the comfortable people living in the more
lucrative markets would be disturbed by having to compete with poor
and hungry people on the labor market, which is why such laws exist.
This is the answer to your question: the greed and indifference of
the comfortable and laws designed to protect their cushy lifestyle
from the poorer parts of the world. Tear 'em down, say I.
-- Eric Watt Forste ++ arkuat@pobox.com ++ expectation foils perception -pcd