If ever Apple needed to open source server and client code for a public good it is with imessages. Yes it has clear limits with a centralized server, but it is realistically how a lot of “secure” messaging happens and it’s very difficult to endorse being tied to expensive hardware. You can say the same about facetime: it is clearly higher quality than competitors in every experiment I’ve tried, but their refusal to i…
Note that I'm arguing from Apple's perspective here. From my own I believe they should absolutely open it up.