[dijit]

If Apple did that, people like me would accuse them of EEE.

We don’t trust proprietary stuff because we’ve been burned by it, if there’s an open standard, even a worse one: use it.

If it’s really that bad, we need to improve the standard.

[codedokode]

As I understand, this protocol is used between an iPhone and iCloud and it being open or not doesn't change anything because there is no alternative iCloud or iPhone.

[dijit]

You’re mistaken, you don’t only connect to your iCloud from iPhones.

You connect from any compatible client; and the effort that has gone in to the Mail client for iOS means it’s a decent enough mail client for non-iCloud mail accounts too.

Apples closed ecosystem is mostly its developer tooling and iMessage.