I saw this in a museum about comnputer technology : It has historical reasons.
Although Dvorak was better, the manufacturer of simple typewriters "overwhelmed" everything with his layout simply because it was sold much, *much* more.
So this became a kind of "industry standard".
It wass then inherited towards computers, as simply bureau machines (remember IBM spelled out ? <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" /> ) .
