I think your Amazon point is rather inaccurate. With amazon people are ordering different products at fixed prices from one seller. In this case, the question

I think your Amazon point is rather inaccurate. With amazon people are ordering different products at fixed prices from one seller. In this case, the question is how do we actually determine the price for one product(say Google's stock) given many buyers and many sellers all with different price points. It's not the same thing at all. Someone/some algorithm has to match offers for sale with offers for purchases. Buyers are willing to buy at up to some price and seller sell at down to some prince. The question is when the matching is done, how frequently and whether you gain any advantage by being faster (other than having marginally more time to analysis). By contention is that you can accomplish this. While this may not work for, I don't think amazon or anything like that has much to do with it.