Listen to Orton's words very carefully when he said this. He said that he bows in allegiance to Bray Wyatt, and he will not challenge for the WWE Title WHILE BRAY IS CHAMPION!
So, he hasn't really given up his shot for the title at WM33. He just won't fight Bray Wyatt for the title, which could mean:-
(a) He challenges Bray BEFORE Wrestlemania, and wins the title, and then Bray gets his rematch at Wrestlemania.
(b) Orton has every intention of wrestling for the WWE Title at Wrestlemania, but will make sure that Bray loses the title before Wrestlemania.
So, he hasn't given up his shot, but won't use it if a particular person holds the belt.
This could be teasing that Orton will turn on Bray and cost him the title, and then claim the shot himself, win the belt off Bray before 'Mania or he is playing mind games, getting Bray into his confidence, when his true loyalty is to the WWE Title.
Maybe Orton enters the battle royal as a suprise entrant, wins, and then demands his WWE Title shot, not at Wrestlemania, but the following week on "Smackdown". Orton wins, and Bray gets his rematch at Wrestlemania 33.