Your link says, and it is also my understanding, that this only affects GSuite users, not the majority of Hangouts users. Is there any indication that most people will be affected ?
Yes. "Hangouts Classic" goes away for GSuite users Oct 2019, and they get migrated to "Hangouts Chat".
"Hangouts Classic" is going to be shut down at some unspecified date after that. All users will eventually be migrated to "Hangouts Chat" - GSuite users are just getting pushed first.
"Hangouts Classic" is going to be shut down at some unspecified date after that. All users will eventually be migrated to "Hangouts Chat" - GSuite users are just getting pushed first.