That would be a truly epic stat, 24 goals in all competitions.. really? Well, no, he got 9 goals in all competitions, which isn't quite as good. Also, stats are good, stats + knowledge is better. For Walcott the large majority of his goals and assists usually come against the worst teams, and for him its usually a hattrick of assists of goals against a team performing laughably badly in their worst game of the season, Blackburn, Blackpool, Spurs in the game they couldn't remember how to pass, etc, etc.
Its the fact that for 89minutes he does nothing, and 1 minute gets on the end of the rest of the teams 89mins of hard work and runs after something and gets a goal. That isn't an entirely awful thing to have at a club, effective is useful, but effective and an actual great footballer is what wins you titles, loads of goals and assists, but no consistency, lazyness and generally not turning up against the big teams and you end up Walcott.
If Walcott were at say, Blackburn, he'd have maybe scraped a few goals last year, nothing else.
The chances the team lay up for him, a better player would score more, a better player would get at least the same goals/assists, and do more to hold possession, defend, win the ball back and win games. Walcott because he's got incredible speed and because some moron plays him at a top 4 club, WILL score, will assist, almost any person who can stand upright would, none of these things makes him a great player. Pires scored more, assisted more, had very little pace, was all about ability, we won things, he worked his ass off, Walcott uses his one gift to get mediocre results.
Its as simple as this, number of times I've seen Messi have a poor game and said to myself, or an entire fan base says to themselves "Why on earth is he at the club", none, Arshavin, none, RVP, none, Cesc, none, Theo, everyone thinks it every other game, because that is actually how completely annonymous and pointless he is SO freaking often.
I'd take a player who is decent and works hard for 90mins every single game and scores and assists nothing, than one who gets 20 goals, 20 assists, in 10 games and is utterly awful in the other 30 games he plays a season... i'd also take a guy like the first one, who gets 20 goals before both the others. To win titles you need players who at their worst... aren't attrocious, you don't even need players who at their best are the best in the world. Milner is almost never exceptional, but he's almost never terrible, Fletcher was never ever brilliant, he always worked for 90mins, made the other team's job harder and made his teams job easier, there are a whole raft of average players at clubs that win titles... the thing they all have in common is they are rarely if ever completely awful.
Arsenal's biggest fault is not that their best players aren't good enough, its that their worst players are THAT bad THAT often. You can not and will not win titles with players that only show up for 1/4 of the games they play.
When Cesc didn't score or assist(rarely) he was still usually the single best player on the pitch, passing, movement, defending, attack, possession, work rate, everything. When Theo isn't scoring or assisting, he's litterally worthless.