I don't think it has to do with poverty. There are Android phones that are as expensive as iPhones. It was just because of incompatibility.
What most are saying is that there’s always been the perception that comes with green messages. When I was on Android (pretty much since the first Nexus all the way to the Galaxy Fold 4), I definitely noticed iPhone users avoiding SMSing with me or in groups, and instead using Facebook Messenger because of the issues that come with group texts involving non-iOS users.
Now that I’m on iOS, I’m aware of the differences, although I don’t particularly care since so many Android devices support RCS.