Insider trading should not result when a perceptive analyst reaches a conclusion about a corporate action through analysis of public information and items of non-material non-public information
(that is, a "mosaic" of information).

This is because the long investor is buying futures at a price higher than the spot price.

Total revenue increases from $400 to $418, so marginal revenue is $18. $2 is the change in average revenue.

The total return includes its dividends and price change.

Both of these statements are true. The law of comparative advantage implies that trading partners can be made better off if each specializes in the production of goods for which it is a low opportunity cost producer and trades for those goods for which it is a high opportunity cost producer. This situation will lead to a minimization of costs and a maximization of output. There must be differences in the relative prices of products across countries in order for this comparative advantage to be realized.
This is because the price of a good reflects the production costs. If all production costs were equal across countries then there would be no incentive to trade since each country can produce with equal efficiency.