@sixohsix In a well designed car flipping into reverse gear at 200 km/h is a counter-intuitive action. Making everything foolproof has it's price.
@sixohsix Sure, but from gear five to six, you would just pull the gearstick back. For reverse you had to slide right first. Moreover you had to pressure it in, since the gearwheels are moving the other direction.
@stefan many cars have it where a sixth gear would be. Yes there's usually a lock on it, but you could easily hit the unlock accidently.