I live in France, and WhatsApp has a pretty big presence. Not a monopoly style one though, there's plenty of other apps used: Facebook Messenger, Skype, Snapcha

I live in France, and WhatsApp has a pretty big presence. Not a monopoly style one though, there's plenty of other apps used: Facebook Messenger, Skype, Snapchat, Discord.. I have friends who have family in other countries and some different apps will be dominant, like Viber, but the common theme is that the only time I've seen people use SMS is when they're unsure as to whether the other person has any other means of communication. Most importantly, I've never seen someone use Google's own non-RCS chat apps, like Google Chat, Google Hangout, Google Allo, Google Talk.. Google has had many chat apps, sometimes just different names for the same thing, but in the end, they have no users here. Google continuously tried to make a dent in that market and failed. RCS is a non-starter if you need to do group chats with iPhone users or send them pictures without a massive loss in quality, as iPhones do not support RCS. As long as Apple refuses to support it, it will continue being a terrible choice in any country with significant Apple user base. An Android user with WhatsApp shares an identical experience with an iPhone user with WhatsApp. RCS on the other hand will drop you back to what cell phone messaging was many decades ago.