Quote from tommo:
I have worked in prop firms for about 6 years and the majority of the people I know making big money do it by feeding off of the HFT systems, they learn to recognise the patterns they create and follow in their footsteps.
If you find your stops are run or you cant get the price you want because of "the bots" and this happens regularly this is actually an edge. If, for example, you find leaning on size doesnt work because it is spoofed by HFT algos then you go against the size expecting it to "flip". If markets have lots of false breakouts then again, there is an edge in that. Trading is about adapting.
The sort of people that throw their hands in the air and say "this is impossible, it used to be easier" will never make it