Let's just think about  well first of all the incoming elasticity argument  right, manufactures greater than one  agriculture less than one  right, that's one reason why agriculture is a declining sector  right, it's also a declining sector in world trade for the same reason  that it has got a low income elasticity  whereas manufacturing had a high income  elasticity    now, consumers like variety  in food just as much as they like variety in manufactured goods  alright, but what's the problem with agricultural goods?they're essentially homogenous alright  wheat is wheat   sugar is sugar.