418
Nothing Phone builds a blue bubble iMessage bridge while Google and Apple fight over RCS
(www.androidcentral.com)
This is a most excellent place for technology news and articles.
This is basically the historical and cultural reason why the US uses SMS and MMS: basically every phone plan has unlimited SMS before smartphones became popular, so any smartphone OS needed to seamlessly support it for adoption. Apple successfully bridged that SMS interface into a proprietary messaging protocol and app even while maintaining backwards compatibility with SMS and MMS, but not the new standard that came out after the iPhone.