It is also a money thing in manufacturing, if you design lots of watches, day date, date no date, gmt around one movement then you simplify the manufacturing process and the stock holding by only needing one movement type.
it happens alot, take for example the BMW X1, they all have the same engine, software ect but it is not set up the same in all models, so in principle they bult the same car just the power is swiched higher in some models.
Apparently the VW group WILL start fitting and building all cars the same, GPS, traction control, power ect you just pay to have it made available to you, I am sure there will be a big market in Jailbraking cars soon