I use a keyboard several hours a day, and I am very fast at it. A few years ago, seeking still more ease and speed, I gave a serious try to adapt to the Dvorak keyboard. I used it exclusively for a full year. I could immediately feel the difference in the amount of finger movement, and within a month or so, my speed was up to where it was with QWERTY. However, it plateaued there, and even after I had become completely comfortable with Dvorak, I never exceeded my old speed. Meanwhile, I found I had lost the ability to use QWERTY, very annoying when temporarily switching to a different machine. I finally gave up Dvorak for that reason, and within a week or so, was comfortable again with QWERTY. So, just one person’s experience regarding why we don’t switch.