unlikely. i think it has more to do with competitive pressures in markets and the elimination of a lot of the less sophisticated participants (partly due to higher frequency trading).
I personally remember enough cases like Steven A Cohen and Galleon and the Gerson-Lehrman group[0], that I assign the probability "likely" to that claim, so if someone says "unlikely" I ask him for his reasoning because I might need to update my estimates. I was not trying to say it is wrong, just understand his reasoning.
[0] https://en.wikipedia.org/wiki/Gerson_Lehrman_Group#Controver...