Exactly. If your complaint is about being locked in but the platform you use is the one everyone has to use because of network effect or otherwise you yourself are locked in with that platform.

And SMS is irrelevant.

The lock-in is obvious: if you're part of Apple-oriented chat groups you can't switch to Android without losing access to those groups, degrading the experience for everyone, or convincing each one of those groups to make the switch to a multi-platform alternative. Claiming not to see this is disingenuous.