Not really. They have ties to specific platforms, just that the platform is not tied to hardware. So it's either installing the app, or losing the connections, same as with the iPhone.
Easier, maybe, but the users are still married to the platforms, now with the added annoyance that there is no cross-talk between the apps at all. Network effect is a huge thing, and the only difference between iMessage and Whatsapp for example is that Whatsapp doesn't have the hardware to lock the users into.
So getting back to the original point, OP bemoans that in order to communicate with some people, one has to have an iPhone. With other apps, you just need to have the specific app. Maybe not as bad, we could say, but the phenomenon is the same: in order to contact some people, you have to install their specific app. No other way in.
Not really. They have ties to specific platforms, just that the platform is not tied to hardware. So it's either installing the app, or losing the connections, same as with the iPhone.