Or Blame MSN, the Instant Messenger, when Microsoft refuse to admit defeat to the Smartphone platform.
So WhatsApp took over in EU ( I believe iMessages or SMS is still popular in France ), UK, SEA, Brazil, Hong Kong. Line in Japan and Taiwan, KakaoTalk in South Korea. Unsure about Australia and Canada. ( They use WhatsApp but not to the extent of countries listed above. )
And it is iMessages in US. I have no idea why that thing even took off. I have tried it dozen times over the years and every few months it has problem with message delivery, people in group not receiving any messages. Poor Searching capabilities etc....
Telegram has gain usage but for different kind of reason. And I dont see it ever being used in the same manner as WhatsApp.
So most of friends just clicked yes and share their Data. It is important to note despite the increasing hostility against FB on HN, and in Tech Circle, most people in the world seems to have no problem with it. I dont see WhatsApp going away any time soon.
Edit: How does this data sharing fit in with GDPR in EU?