"the tremendous popularity and sales volume for the arduino?"
Well the arduino has been around for some time and has built up a strong following, but that doesn't necessarily mean its the easiest to use for beginners or even the best system for them. I'm sure a PIC fanboy would disagree with you, but I do think if the product needs reform to stay current.
You cant just keep telling people a horse and buggy is good enough soon the cars will run you off the road.