I think it started off as a cost cutting measure.
Now it's the norm. Look at the vx range now, most are pretty much the same running gear and engine, just in a different shell. It's lazy and cheap that why it's done.
I can understand people being affraid of RWD, as it's not as forgiving if you f'up a corner. But this is not the car, it's the driver training at fault. How many times are you following a car and the person is breaking whilst in a corner? This is a relatively safe thing to do in WWD car, however a RWD car could potentially bite back if you do this. If people drove like you should, slow down prior to the corner and then power out, this wouldn't be an issue. Now imagine trying to explain to half the drivers out there that you need to keep a positive throttle in corners whilst driving RWD cars. Most won't even know if thier car is RWD or not, let alone what positive throttle is.
IMHO it's a shame that VX and other manufacturers don't offer more RWD cars. I want to start learning to drift when I can afford it, it'll be an Omega for me.