Beginning next year, Verizon will join AT&T and T-Mobile in preloading Android Messages as the default texting app on all Android phones it sells. It’s the final step for making RCS Chat — the next-gen standard designed to replace SMS — the default experience for Android. In the US, that only leaves one large cohort that will not use RCS as a default SMS replacement: iPhone users.
So yes, Apple has iMessages, but only on Apple so that is of zero use in any situation where you have friends, colleagues or family on Android (it's a real world out here). For anything to replace SMS, it needs to be completely cross-platform and able to be the default messaging app. Google supposedly has no plans either to try to introduce a messaging app that supports RCS on the iPhone.
T-Mobile, AT&T, and Verizon are on board — will Apple ever be?