In the big picture there are always constraints .
The confidence with which retailers retain economic stability is attractive to modellers and big picture eco people . The trouble is that politicains and wannabes seem to want to adopt trading as some sort of perfect model. Grocers may know about intersecting J curves ( eg agricultural supply and demand) but they certainly don't need to worry about them ; 16% on everything is easy
Governments who think they can buy the information they need, need to think again . What is the price of invisible cloth? . From the retailers point of view , the customer is always right and.. Why answer all your questions in one when you will pay me individually for each one in order ? Believe me its much easier to subdivide a problem than to put it together again . Beside there is that 16% for each question The more questions the better for us. The margin model doesn't fit good governance cause margins in ecomia are all over the place in terms of reflecting value for money