The other story people are missing here is that even if this wasn't a security issue, iMessage is adopting RCS next year, so the whole blue/green bubble thing will become much less relevant.
rcs is too controlled by carriers for my liking. it's very much an sms replacement, rather than a protocol that treats the cell network as merely a data layer
It's not clear if iMessage will interoperate via RCS, which is what would make blue/green bubbles less relevant. My assumption would be no as they'd cede moat, and there isn't much of a network effect for them to gain from.
> We believe RCS Universal Profile will offer a better interoperability experience when compared to SMS or MMS. This will work alongside iMessage, which will continue to be the best and most secure messaging experience for Apple users.