Nobody uses iMessage outside the US, by choice, even in iPhone-dominated markets. So clearly it's possible to avoid it. US iPhone users have the same choice.
Do you have an example of a place that has a similar rate of usage for iPhones but primarily uses WhatsApp for texting? In the US the rate is 87% for teenagers, I'm surprised it's that high elsewhere.
iPhone has 51% market share in Japan across all age group[1] (and even as high as 84.8% in some demographic[2]). From my 5 years of living here, I’ve never seen anyone use iMessage even once. The dominant messaging app is LINE.
Seems like LINE became the predominant app way back in 2012 (it released even before iMessage did in 2011), so my guess is that it took hold before iMessage ever had a chance, unlike in the US where texting was always the main way to communicate on phones up until iMessage integrated texting to absorb all those users.
