I would respectfully disagree. The very fact that Android users CHOSE not to make Hangouts a success shows it. You see, if Android users had the cult mentality of using everything that was Google/Android, they would blindly use Google's apps regardless of how good the app was just so it would succeed, or takeoff, as you put it. The same way, Apple users are bent on using everything Apple for the sake of using Apple apps. Even when the Apple version sucks. Like using Apple Maps instead of Google Maps when Google maps is just so much better. Android users just seem more open to using whatever app it takes to make them more productive. They're not loyal to Google to the point it interferes with their productivity. You simply just don't see that with a majority of Apple users. Especially when it comes to messaging. For them, it's iMessage or nothing. But with all that being said, regardless of how good iMessage is amongst iOS users, it shouldn't stop someone from installing other messaging apps like Whatsapp, Telegram, Allo, BBM, etc.... These are messaging apps that are equal/better than iMessage with absolutely no restrictions on who can install them. It's really a head shaker.