> it is in Apple's interest to make it a social change rather than just a technological limitation.
It is a technical requirement? How would non-iMessage users respond to the whole group including the ones on iMessage?
When you sit for 5min and think about the whole flow across a bunch of message exchanges every other way there's really no other technical solution than downgrading the whole conversation to SMS/RCS.
The solution is the same one used by every other messaging app: allow iMessage on Android. There is no technical thing stopping them. Instead they actively take measures to prevent it from working.
If people want to group SMS they should open their phone's SMS app. If people want to group iMessage they should all open iMessage. If people want to chat on signal, they should all open signal.
Unfortunately, iMessage is bizarrely both iOS's SMS app and a custom signal-like chat protocol, but the user can't pick between the protocols easily and it switches between them in an opaque way.
It's just a bizarrely bad UX by a company that supposedly is good at UX, and the only purpose it seems to serve is to provide this broken green-bubble experience.
I'd much rather if iOS just had "iMessage" as an app without SMS, had "SMS" as an app for only SMS/MMS/RCS, and then allowed android users to make an apple account and install iMessage (possible with an optional 1-time fee to prevent spam, like having to buy a $700 iPhone and throw it away as a sorta "proof of work" in order to make a iMessage-for-android account. This isn't too different from how some of my friends do this now, with a mac mini in their closet for iMessage which they remote desktop into if they want to chat to iPhone using friends, and use for nothing else).
RCS is not a downgrade, it can also be E2E encrypted but Apple's implementation doesn't use it. It is entirely a business decision to not support the full capabilities of RCS as the iMessage sender system.
The only implementation of E2E RCS is Google's Jibe, which is a proprietary, non-standard version. There is no mention of encryption in the spec other than to say that it's up to carriers to determine. Apple, in contrast to Google's proprietary approach, has offered to work with carriers and the GSMA to define a common set of standards for encryption.
I never said it wasn't proprietary, just that Apple doesn't use it currently. It's fine to offer to work with carriers, but for people right now, it's non-viable to use RCS with iMessage.
While there is no public documentation on Google's approach that I know of, there is also nothing to make me think Apple _can_ currently use it.
There is no authoritative mapping from an account to a single service (e.g. my email address as an Apple account vs a Google accounts vs a WhatsApp account), which also means that if all three of these services say they have an account for me and advertise a public key, there is no way to know that account or public key are authoritative. Google's implementation requires you to use both their client and their hosted service, meaning it almost certainly assumes that all E2E keys can be resolved authoritatively from a single source (Google's table).
You instead need a way to look up accounts in a secure and auditable way across multiple authoritative services, like the IETF Key Transparency work (that isn't complete yet).
It is also important to realize that Apple's support for alternative messaging systems besides iMessage is to meet carrier requirements, not user requirements. Apple's slow uptake on RCS AFAIK was because carriers themselves didn't care, until governments began to regulate it needed to be supported on handsets. The carrier RCS support almost universally is because Google wanted it for Android, which is also why Google's RCS hosted service is by far the most deployed by carriers.
The GSMA needs to define those carrier requirements for E2E RCS, and Apple has stated publicly they are working with them on that.
> it is in Apple's interest to make it a social change rather than just a technological limitation.
It is a technical requirement? How would non-iMessage users respond to the whole group including the ones on iMessage?
When you sit for 5min and think about the whole flow across a bunch of message exchanges every other way there's really no other technical solution than downgrading the whole conversation to SMS/RCS.