It’s an Android thing – Apple users are just getting on with their lives, most people outside of the US use an app like WhatsApp, WeChat, or Telegram (iMessage isn’t even in the top 5 globally). Google is pouring millions into a big marketing campaign trying to get people to think of green bubbles as inferior because they’ve accepted catastrophically botching their messaging play and are hoping to get the EU to bail them out. The more they can get Android users to feel insecure about iOS using the same color it’s always used, the more likely that play is to succeed.
Consider that if Google’s goal was actually interoperable messaging they could have opened up their own services at any point since they shut down federation for XMPP, and they could right now be offering E2EE as a free community standard rather than something carriers pay Google to get. They spent money buying Jibe and are hoping to use RCS adoption to make that more profitable.
IMHO, you can tell that Google's also at fault because there's no Android messaging besides SMS. Android users outside of US (where SMS is not used) have to rely on Whatsapp/Line/Kakaotalk/Facebook Messenger.
If Android had invested in that, they would have something that's very commonly used in everywhere except US.
Consider that if Google’s goal was actually interoperable messaging they could have opened up their own services at any point since they shut down federation for XMPP, and they could right now be offering E2EE as a free community standard rather than something carriers pay Google to get. They spent money buying Jibe and are hoping to use RCS adoption to make that more profitable.