I don't buy this. Customers needed no convincing from Apple. Even where iOS isn't dominant they saw their dropped and expensive SMS/RCS messages and picked up whatsapp.
You are misunderstanding the function of RCS as making different message services compatible. iMessage doesn't exist on Android, hence the necessity of an open protocol.
The problem is that RCS has completely failed at making even different RCS servers compatible.
Carriers like AT&T and Vodafone that were early to adopt RCS never even managed to interoperate with other RCS carriers - you could only send RCS to other AT&T subscribers, or other Vodafone subscribers. Then they all gave up and just adopted Google's servers. So now RCS just means "Google Jibe".
I'm mostly just talking about the noxious white-on-green color they chose for cross-platform chat bubbles. It's a great example of hostile architecture. RCS fixes the cost / reliability problems of SMS, so that annoying color choice will be the only thing they have left to make imessage users feel superior.
Historically, SMS messages have had green bubbles since the iPhone was introduced in 2007. When Apple introduced iMessage in 2011, the showed iMessages in blue, and maintained the green for SMS messages. They are not “cross-platform” messages, Messages only does SMS and iMessage. If you did some reading, instead of getting upset over the longstanding colour of a chat message, you’d know this and not be so angry. Or, like th rest of the world, you would already be using an alternative.
