Color me more than surprised about this out-of-nowhere announcement from Apple. Let's cut to the chase: late next year Apple will replace SMS with RCS on iPhone later next year. I have thoughts.
Firstly, this is not replacing iMessage. There will still be green bubbles. iMessage will still be the default when messaging another person with an Apple ID. However, the fallback messaging with Android phones will now be via RCS. Back in August I declared "I would never bet Apple adopts RCS. They won't. The only way is if SMS becomes deprecated and no longer supported by carriers in a few years from now. Even then, I could see Apple adding RCS in the most barebones and basic way possible in order to hobble the experience."
I was half right.
Tackling the second-half first, Apple is implementing the adopted specification of RCS. In my article quoted above, I mistakenly conflated Google adding end-to-end encryption with the RCS standard gaining E2EE. I was wrong. The native RCS standard has no encryption and Apple is not going to adopt Google's proprietary solution. So just like SMS and MMS that is on the iPhone, RCS will not have encryption. The company said it would work to improve RCS' encryption but that will take time.
My stance that only by SMS going away would Apple adopt RCS omitted a super-important second scenario: government intervention. We all know the iPhone 15 ships with USB-C because of pressure and laws enacted in the EU. It is also why the accessories on the M3 iMac are still lightning: No government pressure in that realm. And while Google has been trying to shame Apple into RCS adoption, the latest move has been the EU possibly forcing iMessage to be opened up. Now, that will not likely need to happen by adopting a modern messaging system.
In many ways, things will look very much the same on an iPhone. iMessage will keep working as aways. If you're texting an Android phone, reactions, typing indicators, and (most important) high quality photos and videos will be sent and received. RCS will be a "nice to have" but right now I don't know how much of a difference it makes overall. Google can't encrypt both ends of the chat nor will Apple adopt any out-of-spec changes to the protocol.
I may have been wrong on Why Apple would adopt RCS but absent the EU's pressure on it and other tech companies, we likely would've never seen this happen. The iPod lived its entire lifecycle as a closed system for the exact same reasons.