"SMS is on the way out". I'll believe it when I see it. Apple isn't going to adopt it because they have no incentive to do so and apple has huge market share. Android hasn't even implemented it yet! We're killing super useful features because 50% (or whatever android market share is) of mobile phones might have something better next year???

Having SMS support as a workaround was huge for signal usability for me. Taking it away burns so much good will.