Not OP, but speaking for myself, one of the biggest annoyances is that both Google and Apple actively resist the actual standard that's already there and widely supported by playback devices (Miracast), and instead push for their own proprietary walled garden solutions (Chromecast, AirPlay).

Google in particular is the worst offender here because they actually had Miracast in Android all the way up to Nexus 4 - and then deliberately removed it! Other vendors of Android devices generally reinstate it in their distros, although I do wonder how long that is going to last (probably right until Google makes not supporting it a condition of getting Google Play certified).