I should have said, "...since MANY diesel models don't...".
Now, whether a safety system component known to repeatedly fail, sometimes at high vehicle speed, bringing a 22K and heavier vehicle to a screeching halt in traffic, creating a dangerous situation for both drivers, passengers, and oncoming traffic can be considered 'poor design' is of course an opinion. And when many consider replacing a $30 safety system component every 15,000 miles as being necessary, I wouldn't call that 'good design' My opinion only.