I've never heard of RCS until this day, and honestly... what's the point of it?
Why would you even touch your phones "vanilla" messaging app?
I know Americans go feral and will try to murder you if you don't use iMessage or whatever, but I never understood why.
Not having to rely on the good intentions of Signal or the corporate interests of WhatsApp/Line/WeChat/Telegram/etc. is a good reason in my book. There's no proof of bad intentions, but if I were the NSA/CIA, I'd set up a service like Signal, tweaked to encrypt in such a way that only I can decrypt its messages.
SMS/MMS is simply terrible to use, but at least it follows the normal "my carrier sends messages to your carrier" approach. The alternative "my carrier sends messages to Facebook to send messages to your carrier" flow adds an unnecessary middle-man, most of which will sell your data.
So instead you rely on the good intentions of your phone carrier? At least there are N third party messaging options that compete as well as open source/decentralized ones that aren't just run by a single business. But I'd rather pick between all of the various messaging options than having another thing that my phone provider needs to do well.
But since all the networks since 4G, there is no more low-level network support for things like SMS. Everything, including voice and messages, is IP- and packet-based. So the only thing the carrier does anymore is to authenticate that IP connection through your SIM card and bind your identity to the phone number. It actually doesn't really matter if messages are "network native" or through a third-party app, there is no more guaranteed timeslot and reliable delivery that SMS used to have.
And nowadays, RCS is also outsourced to Google by basically every carrier.
So RCS is the same as WhatsApp et al., only that the app you are using doesn't tell you that Google will monitor all your communications in addition to the monitoring your carrier does...
It doesn't really matter what the encapsulation is/was, the values of a federated protocol the carrier participates in directly remain the same. The downside is you bundle the privacy to your carrier but that concern should really be solved with E2EE, not trust in a given provider. The upside is your communication service status is tied to your connection service status, and federated out immediately from there. You also gain the ability to fallback transparently to SMS/MMS in the exact same way RCS would work.
Google botched up RCS a bit in order to get it momentum, but plenty of carriers do support RCS natively as that's the only way Apple did it with iOS. Google did at least push E2EE options, but those only landed in GSM with RCS Universal Profile 3.0 and I don't think Apple has given a date for when they will support that profile on iOS. That is to say, the problems here are not inherent to RCS itself but the typical adoption and rollout problems of communication protocols.
All that aside, I'd gladly sacrifice the federated service provider flow if there were actually an equally popular federated solution to latch on to with full fallback capability to aid the remaining transition (+ the protocol actually be designed with radio power saving in mind). It's just RCS is by far the closest thing to that full package vs any other generic data messaging service.
> Google did at least push E2EE options, but those only landed in GSM with RCS Universal Profile 3.0 and I don't think Apple has given a date
This is my guess also. It was published in March[1] this year and I think it was too late to include in this year's iOS 26 release, so possibly iOS 27.
They have promised to implement it:
> "End-to-end encryption is a powerful privacy and security technology that iMessage has supported since the beginning, and now we are pleased to have helped lead a cross industry effort to bring end-to-end encryption to the RCS Universal Profile published by the GSMA," said an Apple spokesperson. "We will add support for end-to-end encrypted RCS messages to iOS, iPadOS, macOS, and watchOS in future software updates." [2]
