https://capitalg.com/team/nick-fox/
"he was responsible for Google's communications products"
At the time, chat was changing quickly from an ICQ-like IM tool towards a more SMS-style, although there was still a use case for gChat in enterprise and professional contexts. Google was losing users to other chat systems, such as ones that only ran on mobile, and used phone numbers, not gmail identities, to keep track of users.
After the debacle that was the first Hangouts launch, they pivoted a number of times more, completely messing up each subsequent rollout, while also having several almost-competing projects fighting for dominance. All of this happened around the time that the leadership was deeply invested in Google Plus and made a number of antisocial decisions.
I feel like expecting them to have created Discord is a bit too much - I think most people didn't realize there was such a strong demand for a chat program structured into 'servers' like IRC.