It is very obvious you are one bias football fan. Being sentimental all the time is not right, sometime say the truth. Arsenal have been this close in winning trophies, they only missed little details over the years but this summer they try to fill in those details.

No excuse form them not winning any trophy next season, after signing a strike, and increasing their depth.
Are being serious right now?
Tell me how will I be looking at arsenal when disappointment has become a normal thing that they usually gives to their faithful and loyal fans?
All your statement here is full of emotions, and it's understandable that you are trying to defend your beloved arsenal, but bro am looking at it as a none fan here, Mikel arteta has spent a lot of time and money for him not to had win something big across five solid years.
If it was person like pep guardiola that was in charge of this arsenal team do you think that arsenal will stay this long without winning anything tangible?
I am not talking with sentiment here as you claimed, am talking base on the fact on ground, that's why I believe that the addition of Gyokeres wouldn't have much impact on this arsenal set up because their short comings has more to do with their mentality than the players. Just give this same set of players to a coach with a winning mentality and I bet  you in the space of two seasons he will deliver something huge, not this things Mikel arteta is doing with this team, so what am trying to say is that a good coach don't have to build a title winning team for ages bro, two seasons is enough to pass his ideas to the players.