#1 Others have spent more

The Gunners finished in their lowest position under Arsène Wenger ever last season and many expected Arsenal’s famous war chest to come into play this summer. Instead, the North London club have done the opposite. This summer Arsenal have spent £47.7m and brought in two players, hardly the kind of activity that will strike fear into the rest of the league.
In contrast, this summer Manchester City have spent £219.87million bringing in 7 players, Manchester United spent £147.96million bringing in 3 players. That’s why these two are now tipped as the clear favourites for the title. This is the kind of money the Gunners must be spending if they want to be considered as title challengers.
To finish 5th in the league means you have a lot of ground to make up on your rivals, not to spend a minuscule amount hoping you can move up one place. Arsenal won’t win the league not because they’re not a big club, but because they don’t spend like one.