I figured it made it more cost effective for using less parts to make it a left hand drive or right hand drive. Less parts = less money. On the column they'd have to switch things around, on the dash they'd also have to switch things around. More engineering, more parts to keep in the parts bin, more money smart has to spend and less profit.
Think of Toyota's center mounted speedo pods. Same reason.
That's why I think it is in the center.