iMessage motivates people to people buy iPhones instead of Android when everyone else in a social circle has it. Why should Apple give up on that? What will Apple gain from making it ubiquitous? It would in fact disappoint many people as now they can't use their phone to distance themselves from the people who don't have that blue circle.
Note that I'm arguing from Apple's perspective here. From my own I believe they should absolutely open it up.
Note that I'm arguing from Apple's perspective here. From my own I believe they should absolutely open it up.