I'd say the opposite - to me IM market seems pretty dynamic, and it's not dominated by one player. I myself use a few different apps: iMessages, Facebook Messen

I'd say the opposite - to me IM market seems pretty dynamic, and it's not dominated by one player. I myself use a few different apps: iMessages, Facebook Messenger, Whatsapp, Skype, Google Hangouts. Then there's WeChat (huge in China), Line (big in Japan and Korea). I've also met quite a few people using Telegram.