Well, I'm the user and I've determined that I'd rather not send private data through their servers, that I'd rather be able to do things like run a proper IMAP, XMPP, SSH or SIP client on my device without disconnections, etc. Those seem like pretty major use cases to me, ones which Apple shouldn't be making decisions for the user about.
If I ran an Apple device I couldn't use SIP and I'd be required to pay 4x as much for a phone plan rather than using a cheap data-only tablet plan for example. That seems prohibitive to say the least...