I am not following the train of thought. All I am reading is yet another wild projection.
SMS is the lowest common denominator across all mobile networks and is the ultimate fallback option for a smartphone if more modern messaging standards or extensions (RCS, iMessage or whatever) are not supported. Degrading SMS means losing 3/4/5G certification and losing the telecommunication authority certification in every single country around the world, consequently instantly losing sales. No sane company that is in the business of selling phones would dare to lose the certification on a global scale. SMS messaging has worked like a charm on iPhones, and I am not sure what the insinuation is all about.
GSMA, the governing body of 3/4/5/6G, has neither adopted nor endorsed RCS up to date, and it is supported at the core network layer only by a fraction of mobile operators across the world. SMS, being a 21st century rotary dial phone equivalent, is supported by every mobile network today however outdated it is. RCS is not.
The original spat over RCS, however, concerned a few sticking points:
1. Google becoming a gatekeeper and holding messages until they could be delivered to the recipient;
2. RCS not being end-to-end encrypted;
2½.Google providing a proprietory encryption protocol with no open source implementation and – *at first* – encryption only being available to P2P conversations (aka FaceBook Messenger style secret chats but not to group chats[0]);
3. Owing to (1), Google gaining the ability to track users via the use of metadata;
4. Only a limited number of Android handsets supporting RCS in the beginning.
I have no stake in the game, but, if I were Apple, I would have not agreed to RCS, either, considering the constraints.
As of May 2024, RCS is still not part of the GSMA portfolio of standards. From the mobile network perspective, it does not exist.
[0] Added later.