There's nothing I will tell you that will make you believe Arsenal had a great season in the Premier League because you already believe it is only when a club wins a title that they are successful, so I will not argue with you on this subject matter.
Why do you think Arsenal had a great season? Maybe you should try and explain, if the people which you quote don’t believe you, then other people might believe you, but if I will be honest also, then I will say Arsenal didn’t have a great season. For the past few seasons, Arsenal have been ending the season in 2nd position, and they repeated the same thing in the just concluded season, that means their is no improvement in Arsenal performance, they remain stagnant.
Arsenal couldn’t win any trophy, so I don’t understand what you meant by Arsenal had a great season. Arsenal didn’t achieve anything, the only thing which I will say they achieved is qualifying for the champions league next season, but apart from that there is no achievement for Arsenal. If they were able to win at least a trophy, then I will say they had a great season.
Trophies will always be the legitimacy to measure a team success, Arsenal have played well in the last three seasons, there is no denying that. But to say they are playing great, I agree with you, Arsenal should be able to win trophies. Actually, if you look at Arsenal performance this season, their statistics have actually decreased slightly, only they still managed to finish in the runnerup position in the standings.
Maybe after going through many challenges and being experienced enough in the competition for trophies, Arsenal could get lucky next season. Otherwise, Arteta should be fired if Arsenal fails again, he has spent a lot of budget to build an ideal squad. Viktor Gyokeres is speculated to join Arsenal, I think that would be a very good recruitment, because it can increase their chances of winning a trophy next season.