How do you know the 500 million sales is due to the Arduino ecosystem?
I used to work in embedded for 10+ years and in the 4 companies I worked at so far, none of the products ever featured AVR microcontrollers. The microcontroller of choice for production was always based on the feature/cost ratio for each application, never on the "is it part of the Arduino ecosystem?" question.
Tinkering with Arduino at home, and building products for mass production, have widely different considerations.