To clarify that, the general thrust is to unify everything onto G+, eventually. Should be fairly obvious and I inferred as much even before I joined Google.

Good luck with that. I fear the day when my Apps domain is forcefully migrated to Hangouts. Hopefully there will be an alternative to Apps by then that is actually worth using.

(One of the people present during my firing needed to summon his boss using internal Hangouts. He eventually gave up, went back to his desk and got his laptop because the experience is completely unusable while mobile. It was hugely amusing to watch, and drove home the dogfood drama for me -- you know what I'm talking about.)