Except those songs weren't staged on their tiny stage as production numbers. The songs were sung, and then the story moved onward.There are other big production numbers in OKLAHOMA! besides the ballet. If they had room to stage "Kansas City" and "The Farmer and the Cowman," they should have had room to do the ballet, even if they had to downsize it a bit. Maybe they just felt they didn't have strong enough dancers for the ballet.