Arteta understands what football is to the public. If you want to win the Premier League right now, its not about how many goals you are able to score in a match its about winning each game throughout the league and that is what Pep Guardiola has been doing right from the start of Manchester City. Right now Arsenals defense is stronger than what it is before, Arteta still bought more midfielders who can hold the ball for long and shoot when necessary. This is how they can win the league. When they concede less goal and win all the matches.
Come on, don't expect too much from Arsenal because they have disappointed their fans too often. It's not about how strong their defense is, not how creative their midfielders are, nor how productive their attackers are, but this about the winning mentality that Arsenal lacks.
Remember that Arsenal always fail at the end of the season and open the way for Manchester City. This is clearly a weakness that Arteta should be able to patch up this season, but it's not easy to change it in an instant. Arsenal's performance consistency is good at the beginning of the season, but they will decline as the season draws to a close, that's the scenario of their failure so far.
What you said is true, in the last two seasons Arsenal have always been good at the beginning but towards the end of the season they lost their performance so they couldn't be consistent. Of course this is one of the influences of mentality, but I think anything can happen in football. Arsenal is not a small team, they are also a big team, of course their mentality will be formed slowly from the experience of failure in the previous two seasons. They don't want to repeat the same mistakes this season.
Moreover, seeing Arsenal's very active movement in this transfer market and Arsenal's current game which is so solid, I think Arsenal has a strong determination to win the EPL trophy this season. The reason is, the failure to compete with Man City in the last two seasons is not only a mentality problem, but Arsenal does not have a reserve squad that is as strong as its main players so when a player is injured, Arsenal's performance also decreases.