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.