Nobody just presses "start" on their trading algo and takes a nap the rest of the day. Even market makers, who have a simple and easily-automatable trading stra

Nobody just presses "start" on their trading algo and takes a nap the rest of the day. Even market makers, who have a simple and easily-automatable trading strategy, have a team of traders constantly tweaking the parameters to their algos. I guess they could hire a second and third shift, but they also could have done that back when stocks were traded on paper and over the phone. The will just isn't there.