via Isn't HFT Getting A Little … Nuts? – Wall Street & Technology.
A nice article where Greg asks when the technology and costs will become too much compared to revenue for HFT for firms to continue participating in the game and/or stop joining in.
As the techno needs increase, we also have to keep in mind costs drop drastically for certain technologies. Some setups, only possible for large institutions are now available to more players. This changes the landscape as well.