The tricky part is what will they do in Gmail? Gmail is used by businesses and currently has Hangouts Chat built in. But Gmail is also used by consumers so will they have allo integrated into that too?
Gmail seems like a big entry point for chat - not sure how they are going to solve that one if they split up the chat products as you suggested.
Are my professional contacts business if we're socializing?
Are my personal contacts personal if they are also clients?
I don't segregate my life cleanly into business/personal and I certainly don't want to double the number of installed apps because marketing.
"I'll have those reports for you by EOD. Please send me a message on Facebook Messenger about that non-professional inquiry."
I just don't see it happening like that. I have people I contact on both Messenger and Slack, and while I tend to keep professional communications to Slack and personal to Messenger, they bleed over.
I'd guess that in the real world outside Hacker News and SV, very few people use email for consumer communication, that role has been taken over by messaging apps. Personal email became a personal business tool, and its usage isn't that different from the regular business usage.
So gsuite, which includes gmail, the new hangouts products and google drive/docs is now focused on enterprise with a free consumer version available.