Competition is already high, and colocating is not that expensive for anyone with the ability to compete. A lot of the loudest criticism of HFT is that it's to

Competition is already high, and colocating is not that expensive for anyone with the ability to compete. A lot of the loudest criticism of HFT is that it's too competitive - a lot of people who used to make a comfortable living from the bid/ask spread are no longer able to due to computers driving down profit margin.