The three speed on the column (after 1947) was not in the way of the "exit slide", and that transmission was standard equipment on light trucks, and it was the most common transmission on non heavy-work trucks (below 3800).
So, the exit-slide was not obstructed when you exited the truck (the family vehicle, in many families) in a village/city at "Sunday-go-to-meeting".
Do you suppose the three-on-the-tree on trucks was introduced to assist in that slide? That column-shifter equipment was certainly more expensive than the three-speed shifter on the box/transmission.
