This is why I don't like to label forward players as strikers. It puts so much emphasis on scoring goals, whereas in a functional team you need them to do so much more.
Look at Watkins. He scored goals, sure, but that's not all he does. A game in which he doesn't score is not necessarily a bad game for him if he can cause trouble and help create chances for other players.
Wesley is much the same; even when he wasn't scoring, he was contributing. With time he would get better, with better players around him it would get easier, and if not for his injury he'd probably be there by now.