I'm sorry, I'm not understanding what you are saying. They specifically DID add races not normally found in Greyhawk because those races are core in 5e. Now, I'll be 100% honest here and say I welcome the changes. I'm all for it. But, it did cause a LOT of consternation in some circles.
My point is, they have to include all the PHB races in a setting. Although, again, to be fair, it seems that the Magic The Gathering D&D settings get to break that mold. We'll see if that holds true in later supplements.