While Apple could continue to use green text bubbles for Android and keep the blue text bubbles for iOS users, RCS support should give both iOS and Android users access to the same features that iMessage offers. At the end of the day, this could eliminate the teasing and bullying that teenage Android users have had to deal with from teen iPhone users for years.
Apple had been loathe to support RCS because it considers iMessage a major selling point for iPhone buyers. But iMessage is not disappearing from the iPhone at all; once RCS support is implemented by Apple, RCS will be a separate messaging platform from iMessage that can be used when available. SMS/MMS will still be offered as a backup.
The main thing to keep in mind is that Apple is that iMessage will remain the platform used by iPhone users when messaging each other one-on-one or in a group. RCS will be a separate platform that can be used when iPhone users want to message Android users. If you’ve ever seen how poor the image quality is of photographs and videos shared between an Android user and an iPhone user, you’ll be looking forward to the day when Apple’s support of RCS begins.