I've seen a lot of chatter on the web since Google announced their new services;
Allo & Duo: https://googleblog.blogspot.co.uk/2016/05/allo-duo-apps-messaging-video.html
The conversation seems to be why are Google releasing new products instead of updating existing older ones.
I think this is because Google don't want to put all of their eggs in one basket, their previous strategy was tie everything into Google+, that didn't get the uptake that Google expected and after significant backlash Google reversed that strategy.
In the technology world first impressions last, people will try new products and services but if they don't wow them they won't return. It won't matter what new bells and whistles they add laterthey will only return if their friends start using the product but if everyone had that same first impression that isn't going to happen.
Google is such a big company full of geniuses, if they think of a new way to do messaging why wouldn't they see if it works, just because it may overlap with another product isn't a good enough reason not to? When Google sit still other companies take over, if Google don't build these products then someone else will. The new tactic seems to be throw a bunch of stuff at the wall and see what sticks, why waste years again by only allowing one messenger app when you can let the public pick and choose what Google messaging app they want to use.
Do people ask Facebook to Merge Facebook and Instagram? Or to merge Whatsapp and Facebook Messenger? They serve different purposes to different people. Google seem to be following suit but first they need the apps, this is stage one.
This makes perfect sense for a data driven company, to rely on one products success seems like a strange concept for such a diverse company with billions of potential customers. The only question is will this dilute the Google brand? Some may already argue that this is already the case.