> Is there some quantifiable financial thing that would regress to whatever terrible situation we were in back in 1990 before HFT was substantial? Yes, trades

> Is there some quantifiable financial thing that would regress to whatever terrible situation we were in back in 1990 before HFT was substantial? Yes, trades would cost a lot more. Every time your money was put into a stock, some middle men would take more of it than they do now. Trades would take longer, you might not get the price you thought you were getting when said buy or sell because the price might change in the time it took some dude to go manually buy or sell the shares you requested. That directly affects everyone with a 401k or stock. HFT has eliminated a large swath of useless middle men who were gouging you for money: those middle men are pissed they've been obsoleted and lost access to easily profit and are the now pushing to regular HFT, so they can go back to the good old days of bigger profits and more room for middle men taking a bigger bit of the average mans investment money. HFT saves every market participant money, except the old school traders whom they've largely obsoleted.