270
Some Beeper users say Apple banned their Macs from iMessage
(9to5google.com)
This is a most excellent place for technology news and articles.
The average American is not tech savvy.
(Which is surprising, given that the US has arguably the strongest software development industry in the world.)
Most Americans just use the default apps installed on their phones. Facebook Messenger is really the only non-default messaging app with mass market penetration, and that's because most Americans already have Facebook accounts.
Americans just don't want to sign up for new accounts or learn new apps. Therefore, iMessage won by default.