I'll second this complaint. Though personally I try to use Signal with my friends and this led to the strategy of "it's like iMessage, but cross platform" for those who aren't security conscious. Sure, not exactly, but close enough. There's a lot I like about Apple, but the closed walls are a major hindrance. I really wish companies would see the value of open source or at least open protocols. I mean hasn't our entire technological framework essentially been built due to source code being available? Certainly we can point to the internet, android, any programming language, linux, and many other common systems that we use daily (knowingly or unknowingly). I mean it's like turning down free work... Why?