Arsenal have scored 36 league goals in 11 Premiership games this season. That is a rate of 3.27 goals a game and if they continue at this rate for the remainder of the season they will have 124 league goals! No team in the Premiership era has ever broken the 100 league goal barrier, with Manchester United recording the highest with 97 leagues goals in the 99/00 campaign.
Arsenal fans should not jump at this as the team from North London have also conceded 14 league goals and are therefore projected to concede 48 league goals. Manchester United hold the record for the most league goals conceded by a team going to win the Premiership, with 45 league goals in 99/00.
You may argue, it is not a question of goals scored or goals conceded, but rather the goal difference. That may well be, but a team winning 1-0 three times in a row are better off than a team winning 4-0, 4-0 and losing a game 1-0. Arsenal are unlikely to maintain such a rich goalscoring rate and therefore will experience periods where the team will have to defend better.
Finally, it is worth adding that Chelsea and Manchester United are projected to score 92 and 73 league goals this season, respectively. The projected conceded league goals for the same clubs are 25 and 38, respectively.

Wenger would swap half those goals for points that put Arsenal top off the league. Football is a simple game; you win by scoring more than the opposition, and Arsenal can’t do that consistently enough to beat the ‘big two.’
I think the underlying trends in football have a big impact on what happens on the long run.
A large goal difference suggests a team is highly competent.
Since this was written, Arsenal have scored 4 goals in 4 league games, and in all competitions they have scored 6 in 7 goals. It is to be noted that this patch coincides with the injury to Robin Van Persie aswell as Bendtner being out.
“Arsenal are unlikely to maintain such a rich goalscoring rate and therefore will experience periods where the team will have to defend better”
I think that says it all. The past 4 league games Arsenal have had to defend better and they haven’t.