Who is doing better than him? Welbeck? Giroud? Iwobi? They're all as bad as each other! Even Lacazette is firing blanks now. Maybe a change in personnel is what was needed under Wenger.
Walcott gets goals because he's the single most selfish player I've ever seen play football. When he came on the other day he did the same he always does. Someone passed him the ball, he saw an opposition player within 10 yards, he never tried to run at the fullback, he never tried to progress, he passed it instantly back to Bellerin then he ran up to the box.
He's done that for a decade, 98% of his time on the pitch if he's getting the ball not near the box he gives up his job and immediately passes back to someone else then runs into the box. He gets goals because there is quality around him and we play plenty of different levels of teams. He's also fast with good passers behind him, the goals he got against City in the 6-3 were because in part he was so poor defensively and retaining the ball on the wing that we got destroyed, and a result of being so completely dominated is City stopped defending which left gaps for someone to run into and nab a consolation goal. That is how he's always managed to get goals, but a fundamental part of that is he doesn't do his job on the right wing, he doesn't even try.
In 10 games he'll get 5 goals, 1 might have an effect on points, 3 will be consolation goals and one will be a fluke but in 9 out of 10 games he'll be completely useless in 80 minutes of the game, we'll lose a few of those games and part of the reason is the utter inability to be a threat throughout the game, left wings love it when he plays, with the ball the opposition knows they can double up on the fullback and ignore Walcott, defensively the fullback knows he can just stand roughly in Walcott's way and he'll give up leaving the winger to stay further up the pitch and be ready for a counter.
Welbeck is awful in the box and technically inept, but he at least tries to carry the ball from the half way line to the box, he just can't do anything when he gets there, Iwobi has just become useless under Wenger but I think a new manager and better training, confidence and better tactics and in 2 months he'd be back to his old self and well beyond how Walcott or WElbeck can play. Giroud himself plays great as a striker, far far better than Walcott at finishing in the box and just as useless outside of it.
The thing is Walcott could be good, he could be better, he has like, I think a good 7 or even 8 times in a whole decade decided to actually run at defenders and beaten a few, even scoring after such runs now and then. He is, lets be clear I'm not saying he's Messi quality or even close, but imagine if Messi though phenomenal at dribbling just decided he didn't like it, he didn't like getting kicked so he just never ever bothered. Messi would be vastly vastly worse player if he simply refused to dribble... this is how I view Walcott, he's a player who could be pretty good but he absolutely refuses to actually work hard. He refuses to do 50% of his job, he sees a fullback and he turns around and passes off, he doesn't like the responsibility, he doesn't like the challenge, he doesn't like getting kicked and he backs out of almost every option he has available to him.
The 10 games in a decade he's played at his full potential aren't what you measure him on, it's his average, which is a giant girl of a player who never tries nor plays anywhere near as welll as he could.
Iwobi and Welbeck may be playing trash, but they try, they aren't scared of the ball and they don't back away from every option.