I live in indonesia. there was a blackberry boom in 2010 that sort of push a lot of people to get blackberry, because you can use blackberry messenger (BBM) and not have to pay for SMS. if you want to get in touch with some people, you'd have to buy a blackberry because they don't like paying charges replying to your text.
you have to realize that at that time people were still using symbian phones. some people use androids, few uses iphone and very few use windows phone. those majority of people who use symbian, they found that moving to bb os is much easier than to android/ios/wp due to physical keyboards.
so in short I got my first 2G blackberry curve in 2011 to complement my windows phone 7. it's stupidly overpriced when I bought it considering whatsapp was already available (on 1 year trial basis). it doesn't last long because people actually realize how crappy bb hardware is compared to iphone, androids and windows phone. whatsapp starting to gain dominance in the region as it is no longer 1-year-trial basis and at the same time two things happened in late 2013: symbian was discontinued, bbm was also launched in iphone or android.
now there is no sense in getting blackberry phone because what people needs (BBM) is also available in other phones. as whatsapp gain dominance, in introduced voice calls in 2015 which encourages people to ditch BBM in favor of whatsapp. remember what I said about people reluctant to pay for text charges?
blackberry did nothing until 2017 where it launched indonesian only aurora model with subpar performance. it was not surprising because the phone was developed with TCL. it was competing with samsung, sony, lg, htc, asus, xiaomi and so much other phone in 2017 it just couldn't keep up.
both google and apple played a part in killing windows phone, but it did nothing of significance to blackberry. it was whatsapp who killed blackberry.