I'm sort of surprised at the positive tone here. Sure, it's nice for non-technical people to enumerate a lot of nice to haves, but just asserting something doesn't make it true or possible. As one example, making "core messaging functionality interoperable". How exactly does that work with end-to-end encryption? I suppose we'd need some sort of open system and protocol for all the tricky key sharing stuff? That would…
Exactly how we deal with everything else that works across platforms: standardization. We've done it at least once before (SSL/TLS), I'm sure these rich and "amazingly smart" companies can figure out how to achieve it once again.
> Isn't there, again, some hardware security issues in play with that?
Is there hardware security issues with accept CC details on the web? Assuming the computer itself isn't compromised, the web seems to (again) have figured out how to deal with it across platforms, both OSes and browsers, why can't phone OSes do it?