Didn’t Steve Jobs originally say that iMessage would be an open protocol? Or am I misremembering that?
Steve Jobs went on medical leave from Apple since January 2011.
Wikipedia says iMessage was announced June 6, 2011 by Scott Forstall and launched October 12, 2011.
Steve was at the announcement but died a week before that launch.
⇒ I think it’s unlikely he said anything about it in public.