Take a look a Chelsea and United, how many managers have they chopped and changed over the last few seasons?
Both big clubs and both way worse off than Arsenal, both clubs would love to be in Arsenal's position right now.
Instead of chopping and changing twice a season, they've stuck to Arteta and are trying to get a title over the line in which they are close to doing.
Chelsea and United are a million miles off winning a league title and both have changed managers, players more than Katie Price has changed blokes, so sacking mangers isn't always the choice.