People love to rail on HFT, but at this point, its really not that profitable. It's just a reality of trading in the markets. There was a blip of time between 2008 and 2014 when HFT was extremely profitable. Those inefficiencies have been gone from the market for years. People were whooped into anger about how much money was being made, at this point its a complete non issue and needs to be removed from the highlight…
Adding to this, HFT is a product of rule 612 of Reg NMS (the sub-penny rule). Markets are not allowed to show quotes in increments of less than $0.01 for most names. Since traders cannot compete on price, they have been forced to compete exclusively on speed. The impact of such regulation was tested by the SEC recently with the 'tick size' program. Instead of reducing the minimum increment, some names saw it increase…
I'm not sure anyone knows for sure why this happened, but the best theory i've heard is that the reduction in tick size reduced the expected profits of market makers, because they are collecting less spread on every contract they turn around, while not affecting their potential losses, because external factors which cause the market to jump three basis points will still cause it to jump three basis points. Halved regular profits divided by constant occasional losses equals no longer worth bothering with.