You might have been a victim of the last point made in my posting. Although theoretically you should have been visible, you fell within the particular area of the fields of vision that renders oncoming objects difficult to perceive.
I used to be sceptical of the 'legitimised' SMIDSY, called motion camouflage, as documented in
Bike magazine until I started to pull out into a main road and a car appeared out of nowhere to my right. It gave me one hell of a shock. My observation skills are very good. They had kept me out of trouble for over thirty five years of road use as a cyclist, motocyclist and motorist yet here was an instance where my observations were negated by motion camouflage and I failed to register the presence of an object as big as a car!