I'm not a messaging historian, but according to Wikipedia RCS group was formed in 2007. Apple's iMessage was launched in 2011, which means it had been in devel

I'm not a messaging historian, but according to Wikipedia RCS group was formed in 2007. Apple's iMessage was launched in 2011, which means it had been in development for some time. Especially being Apple, they would not pick an external pre-standard and run with it when they built their success on in-house design and control. It would also be a huge gamble to build around someone else's young standard. Do you remember phones in 2011? The Android-based phones were wildly different from each other (often flawed in unique ways). There were still popular Nokia based phones. Apple almost certainly did not target "lock in" as their priority when building their phone software. They targeted "stuff we can control which won't blow up in ways we cannot understand or prevent". (I do admit their focus shifted after Steve Jobs died, but that was later.) But also realize the carriers were in heavy competition for decades. I've worked with/for telecom companies off and on for a very long time, and the only coordination really happens when one big company buys another and has to try to integrate things.