wait..i was ok with this not being in pc..but how can you exclude this on console...silly
Because data shows almost everyone is in party chat instead of game chat.
Because data shows that you can save your game bandwidth overhead by not reduplicating functionality, taking away bandwidth you could have used for game state messages. Voice chat is not free in terms of bandwidth.
The limit of 8 people and whatever it is on the One is a first party issue, not a developer's issue, and it can be increased later.
Anyone who played Halo 3 on 360 can tell you that party chat killed off social chat. It came out almost halfway through that game's "run" and proximity chat died overnight.
Then Reach shipped with options to mass-block social chat.
Then Halo 4 shipped with no ability to hear the other team at all.
Destiny shipped with no social chat whatsoever and when they added it in after everyone complained about it.. nobody fucking uses it.
Voice chat isn't unavailable, it's right there in the OS.