It's a phone that costs about 4x the gross monthly wage of an average Indonesian.
About in line for an American to buy a new car.
If 5% of population (14M people) can afford an iPhone, it's already bigger than a lot of potential markets around the world. I'm sure they do a much more thorough analysis at Apple though.
.. You should travel to Indonesia. Almost nobody has Apple products, the majority of people such as gig workers (GoJek) earn less than $10 per day. GoJek riders earn more than average, labour is incredibly cheap in Indonesia.
vivo and similar low-cost Android phones for the Indian market are popular.