It's not a problem for Android because every messaging app
is cross platform. The only one that isn't is iMessage, so by definition this isn't a problem that exists. But also in the US, it's nearly all iPhones, so there just aren't any groups of Android users with one iPhone friend.
More I think they are just really susceptible to marketing efforts by companies like Apple who tell them that it's a bad user experience to have multiple apps, and your own personal user experience is supreme, so people adopt and believe that. And for the people who don't, you can almost guarantee they have at least one "Apple fanatic" in their circle who will preach that gospel to them routinely.
Then there's the social status symbol of "Apple" that has become a big thing in the US. The killer on top is the invasion of the social sphere, partiuclarly with younger people, where you are bullied and isolated for not having an iThingy, and you've got a perfect recipe for Apple.
At some point I think it's got to come back around, but unfortunately that time isn't looking soon as it's trending heavily in the wrong direction right now. It's so bad now that "iPhone" has come to be a generic word for "mobile phones" and "iPad" a generic for "tablet." Just a few days ago I heard someone say something like, "Oh is that an Android iPad? aren't those just cheap knock-offs?" When this is the level of thinking in most of society, it's not hard for a company like Apple to manipulate to serve their ends.