Network effects aren't a big deal when it comes to messaging. There was a time when people thought iPhone wouldn't be able to overcome Blackberry because everyone was on BBM. In the last couple decades we've seen people go from ICQ to AIM/Yahoo/MSN to Google Talk to Skype to Facebook Messenger to BBM to Whatsapp/iMessage/Instagram, with dozens of smaller options like Kik, Viber, Line, Signal, Telegram all hanging around. It doesn't take much to cause another shift in the space.
That sounds nice, but in reality most of my extended friend group has migrated to WhatsApp over the last 10 years and is unlikely to change anytime soon. Interoperability would be nice (like we used to have) but that will never happen until Apple stops using their lack of interoperability as a way to ostracize young people and sell more phones.
