And how does that explain Apple not having an issue with you using iMessage on a desktop Mac? Again: we know the anti-spam mechanisms Apple might have in place

And how does that explain Apple not having an issue with you using iMessage on a desktop Mac? Again: we know the anti-spam mechanisms Apple might have in place do not rely on people being unable to root their devices as iMessage runs on desktop Macs (as well as on jailbroken iOS devices, btw, without any need for subterfuge). Apple simply does not have this restriction that Google is imposing on RCS. Apple's anti-spam comes from a combination of server-side analysis, having a centralized way to enforce bans, and tying accounts to phone numbers, none of which seem to involve banning jailbroken devices as, again: Apple doesn't. (FWIW, I don't know off the top of my head how Apple ties your iMesaage account to your phone number. I vaguely remember that it involves functionality implemented by the carrier, not just trusting the client, and as RCS definitely has to be supported by the carrier there is no issue deploying such here. Regardless, not only would trusting the client be ridiculously stupid in case it ever got hacked, we can continue to lean into the analysis that Apple does not nor have they ever banned jailbroken iPhones from using iMessage, and so we don't even have to dig deeply: we know their security model doesn't rely on something they don't do.)