I don't understand why can't just Google copy iMessage exactly as it is. They can just tie up the chat app like Hangouts to the Gmail ID and just build SMS and

I don't understand why can't just Google copy iMessage exactly as it is. They can just tie up the chat app like Hangouts to the Gmail ID and just build SMS and Video functionality into it. And make it available by default. So when I want to SMS, Text, or Video I don't need to "think" which app to use. They can just get rid of their Messages, Allo, Duo, etc and just stick to one default messaging app.