Nothing is impossible, Arsenal is doubted only because their mentality is as bad as in the previous season and no one knows what will happen this season, maybe they can get up and learn from what happened last season.
In terms of quality, Arsenal's team is as strong as Man City and Liverpool, so they cannot be underestimated.
In my opinion, in terms of percentage, these three teams still have the same percentage to win the title this season, the same goes for Liverpool even though they drew against Manchester United this week.
Currently, Arsenal has bad winning mentality but their performance very difference in this season after holding draw Manchester City on their home match and lead the top position until playing 31 matches. Its meant left 7 matches for Arsenal keep their consistency performance on always has winning mentality to get Premier League trophy in this season. Arsenal has advantage with 9 goals difference from Liverpool because both teams have the same points awhile and Premier League regulation count with most scoring goals not head to head.
Looking on matches left, Arsenal has some difficult matches against Chelsea, Tottenham Hotspur and Manchester United with most of left team opponent want to defend their position at Champion League spot place for Spurs and Manchester United want to reach UEFA Europe League ticket next season by finish on 5th or 6th standings position.