I am wondering why they don't just integrate groups features into Google Apps (where you could use Sites and Docs to do this same thing). It leads me to believe

I am wondering why they don't just integrate groups features into Google Apps (where you could use Sites and Docs to do this same thing). It leads me to believe (knowing nothing about the reality) that Groups was built on some different underlying technology stack that makes it more difficult to integrate... I had a JotSpot account that eventually became a Google Sites site, and the main thing that didn't migrate over neatly was the discussion forums. Also noticed this message on there: "Google Groups will no longer be supporting the Welcome Message feature. Starting January 13, you won't be able to edit your welcome messages, but you will still be able to view and download the existing content." Would it kill them to tell us why?