Ask HN: Why did hangouts(Google talk) not take off as it should've?

I'm more of a old school web user (started much before the smartphone revolution). And back in the day, I remember this nifty app called - google talk for the desktop, which was leagues ahead in terms of speed and ease of use compared to other apps (ex: yahoo chat). I used it for a long time, and even in the smartphone era, I stuck with it for some time even after it became hangouts. I might still prefer to use it, but most of my friends have moved onto whatsapp or skype for group messaging / one-one messaging. I feel Google had this incredible opportunity, but failed to cash in on it leading to other clones like WA, FB messenger claiming the top spots.

Any particular reason why google neglected the hangouts app ?