first off, you're stretching that point to make it work for you.
secondly, your main train of thought seems to be THESE SYSTEMS SUPPORT SO THIS OTHER ONE THAT DOESN'T IS SHIT BECAUSE IT DOESN'T. Admittedly, sometimes there are features that should be system-wide, but there are others that don't necessarily need to be universal. Voice chat, while nice, is one of those. As has been pointed out several times in this thread, also has quite a few cons to match the pros.
1) 12-year-olds spouting profanity and calling you names for no reason
2) You can use bluetooth headsets
3) If you want to chat whenever like on the 360... then use a 360. This is a different system. Get over it.