In a surprising move, Apple has announced today that it will adopt the RCS (Rich Communication Services) messaging standard. The feature will launch via a software update “later next year” and bring a wide range of iMessage-style features to messaging between iPhone and Android users.
Apple’s decision comes amid pressure from regulators and competitors like Google and Samsung. It also comes as RCS has continued to develop and become a more mature platform than it once was.
Let me know when you can use RCS on an Android phone without Google Play Services outside of Google Messages
I think this is because the carriers were slow / refused to host RCS on their servers so most carriers make you use Google servers.