King's Indian move order Isn't 1. d4 Nf6 2. c4 d6 (Old Indian Defense) a more flexible move-order than 1. d4 Nf6 2. c4 g6 (King's Indian Defense)? 

I don't see why any Black player who wants to play the King's Indian would avoid the former move order.
It's actually a less flexible move order. The bishop will go to g7 in either case, but now black can't go ...d5 in one go. Only play this if you want to put the bishop on e7 (the Old Indian Defense)