Trade barriers are subsidies to favoured groups. Except when erected to protect animal, plant or human life they are essentially rewards to those corporations who have most muscle over government. So the collapse of the Doha Round is particularly depressing for those, like me, who believe that economies and governments are supposed to serve natural persons, as distinct from corporations, not the other way round.
The broader question is why governments are now so remote from their populations that the interests of corporations matter more to them than those of the people they are supposed to represent. Is it a function of size alone? There does seem to be circular relationship: corporations lobby for subsidies and spending on a certain type of infrastructure; a type that favours large corporations at the expense of small businesses and the environment. So our economic system becomes more complex, and more dependent not just on that complexity, but on the growth of that complexity. Interdependence, alienation and the remoteness of decision making all rise inexorably. People lose sight of how their best interests will be served. Somewhere along the way, the system becomes more important to policymakers than the wellbeing of the people whom it's supposed to serve. But the system resists organic change. Its main beneficiaries, large corporations and government agencies, find it easier to feed at the government trough.
The collapse of the Doha Round blights the prospects of millions in the developing countries. It will keep many of them in poverty and despair. Unfortunately the connection is too obscure and slow-moving for television, and our elected representatives and their paymasters in the large corporations will carry on regardless, subsidising the rich at the expense of the poor.