Wouldn't it be nice
If we could have a Google Voice / Android service that could be the equivalent of iMessage, and then have iMessage and Google Message/Voice allow full-fledged communication. What would be even better is to allow IP calling between the two services, have ti available cross-device/cross-platform. Surely these two behemoth companies realize that their customers are fully integrated within their walled gardens and won't budge so now would be the time to allow this to happen. It would allow us to remove all the other messaging apps we have installed on our devices and really clean things up a lot. At the moment everything defaults back to SMS and maybe RCS in the future but I don't think this goes far enough.
https://www.theverge.com/2018/4/19/17252486/google-android-messages-chat-rcs-anil-sabharwal-imessage-texting