..or it could be an opportunity for them. Apple relies more and more on services for growth. For instance, why not make iMessage into a cross-platform app, as a real privacy-focused competitor to Whatsapp, Telegram etc?
Lock in - how many people are locked into Apple because of iMessage? I think it's just an ancillary service to most people, with WhatsApp, Messenger, Telegram, or WeChat in China being their main IM app. The longer this is the case, the less relevant iMessage becomes.
I see a lot of upside and not a lot of downside for Apple here