Well first of all I make it a point not to read anything that has the word " programming", ‘neural networks’, data mining and automated. The moment I see anything along that line, i flip a page or browse for something else.
So, my knowledge about this is 0. I might not be in the loop of insider information.
But this is what I believe. The market is a closed system. At the end of the day, its finite, and if one person is gaining somewhere, than another is loosing elsewhere. Which is completely different from stocks or commodity. The big players, who use the market to change currency from one denomination to the other, and who hedge for protection against changing foreign exchange rates etc, end up looking for a balance. And most end up around that balance.
In such an ecosystem, an anomaly will quickly be swallowed by the market so that it can adjust itself to be back close to equilibrium. Unless the automated systems can learn by itself and adapt, as suggested by neural network purveyors, than most automated trading software or robots only have a short lifespan of profitability, assuming that they were profitable in the first place.
In other words, the edge of the automated system will quickly be neutralized by someone else trading with something else along the way.
This is apparent when I say the markets have been the same through out the years, but it changes.
Look at correlation for an example. I use to use it as one of my main entry rules. Now I am forced to abandon it altogether and adapt. The biggest weakness preventing automated systems from being very successful is its exacting and precise nature, with zero deviations from its programmed intentions. Which, unfortunately, also happens to be its biggest strength.
So an algorithm, which has decoded market movements will fail before a specific time period ,t, because of the very presence of the same algorithm in the market has changed things and the original algorithm can no longer be accurate. Now, the original algorithm cannot adapt to that. It is by nature, self defeating.