Apple makes software to help Apple customers.
Apple software made to help Apple customers doesn't help Android customers.
Amazing.
I understand your point, Gnasher, but this is a communication protocol. By definition when you communicate you want to communicate with the widest group available. What if you couldn't make phone calls to someone with an Android, Windows or Blackberry phone because they all had different standards? Seems ridiculous, but if they didn't all agree to use a telephony standard it would be the case.
Companies in the business of communication, and making a profit are walking a fine line. They want to make their product as irresistible as possible, but also need to preserve their business model. In Android's case, Google doesn't care about open standards, because they don't make their money on selling the OS or the hardware. They make their money when the most people use their product, and they sell those users to advertisers. Microsoft and Cisco have similar business models in that they want to leverage their already large enterprise customer bases to make their communications products seem to make the most sense and continue to sell OS/licensing (although Cisco makes a lot of money selling hardware, also).
Apple's business model relies on you buying into an ecosystem. It's a stable, secure, reliable and easy to use ecosystem, to be sure. But it relies heavily on selling a premium hardware product, and they have no enterprise leverage to speak of as a carrot for business. As VoIP technology continues to evolve and mature, I fear that the average consumer's almost invariable tendency to go with the cheapest alternative will segregate Apple users into a small (by relative size) group who will not be able to communicate with the rest of the world, and who will eventually get frustrated by this, and end up leaving the ecosystem specifically to be able to communicate with others. This is why Apple should explore common sense ways to make their VoIP communications more open and accessible.
If you watch any of Steve Jobs' keynotes when he came back to Apple and introduced products like the iMac, it was obvious that Apple understood the power of the internet before and to a greater extent than a lot of other computer makers at the time. But Apple's drive to make "insanely great products" cannot be the dogma that marginalizes their users in the very important world of VoIP communications.