I know next to nobody who uses Whatsapp outside of my European friends. Meanwhile, large amounts of my friends back here in America use Snapchat regularly, and my friends over in China use WeChat and QQ above everything else. I have trouble believing that there's any standard messaging app for the world at the moment. I do agree, though, Snapchat is not lightweight and occasionally crashes on launch on my Galaxy S5.
Where are the people you know in the Pacific Rim areas? Because, for example, in Japan, I've been under the impression that Line dominated the messaging app market. I think WhatsApp has failed to control the entire market because there's other apps with different kinds of functionality that different regions prefer.
Here in the Netherlands, which has the highest percentage of WhatsApp users in the world, it got really popular when Internet bundles became much cheaper than sending relatively expensive texts (15-20 cents per text). Which was around 2009 - it's snowballed from there. I literally don't know anyone with a smartphone who I can't Whatsapp.