You also have to consider the size of kill cows. They are getting smaller so it take more of them to meet hamburger requirements. Big cows are leaving at a much more rapid pace than the 1000 lb'ers. A short bred cow around here over 1400 lbs has very little chance going back to the farm no matter what her age is. This is where we are losing good quality animals.
In my one and done group this year I bought a 1450 lb Brangus cow that the vet called solid mouth bred 5 months. She was not real pretty, a little bit spooky and has a lot of ear. I only paid about $100 over kill prices which with her weight was a lot of money for a one and done. In the three months I have owned her she shaped up, calved a nice bull calf and calmed down to where she is no worry to be standing 5' from her. Her udder is as good as you could hope for. She will join my main herd even though she is bigger than I like.