1) Why is it not possible, has one of the dev team or a person equal to them said it isn't?
2) With a demand factoring into the price it would make it easier to make very high credits/hr, IF you knew where to go. The way I see it that most people that have posted don't mind a little work to supply their other non trading characters, they just don't want to spend most of their time trading rather than with their other characters.
From what I have read power traders just want to make the needed amount to buy whatever cap ship they want. By having a variable price it would encourage who ever is trading to be more involved in the game therefore enhance PR which is what we all want.....right?