It must be wonderful to be able to diagnose the causes of collisions from half a world away. Having only ridden thro' places like Iran, Turkmenistan, Kygyzstan, Tajikistan, Afghanistan and every 'stan in between, before riding down thro' China, they cannot possibly have had any idea of how to ride safely in that kind of traffic and on those kinds of roads.
To give yourself some idea of how little experience and skills they had, watch:
http://bikeportland.org/2013/02/18/f...998#more-82998
Oh, by the way, they did have mirrors.
and speaking as one who was knocked off his bike whilst wearing orange waterproof trousers, yellow cape (old-fashioned type), 3 feet of 1.5" reflective strip on my paniers, reflective sidewalls on my tyres, front and rear lights, relective anklebands, pedal relectors, reflectors on the wheels, I find the OP's faith in the efficacy of lights really touching.