@[deleted]: Easier said than done. Also - while Walcott may have had less variety at the same age, he still had a few specialist skills. In particular, being able to use his pace to either cut it back or finish. He's similar to Giroud in someways.
Chambo might be technically better at the same age but he's not showing any outstanding qualities, aside from his dribbling, but we've got plenty of players who can do that. And he can't defend so that makes him a liability.