Fwiw there's something wrong at the heart of Arsenal football club. And as an outsider looking in (certainly one who can at least respect the old rivalry) it's been there for at least 12 years.
I've seen a mentally strong team with the likes of Adams, Viera, Llundberg, Lauren, Toure, Parlour, Ashley, Henry gradually leave and the transition to the mentality of the likes of Fabregas, Flamini, Eboue and it's been there ever since. There were still some of the old guard left like Silva, Bergkamp, Toure, Lauren, Campbell when that transition happened but I remember in that moment exactly that shift in mentality and the lack of focus in the new blood coming through. The old guard that were there became marginalised. I remember Sol Campbell walking out in the middle of the League Cup semi-final iirc and that was the end for him, talk of the new guys in the dressing room disrespecting Wenger, undermining the wisdom of the experienced players, then Toure leave, Silva leave, Pires leave, Henry leave. And what you were left with set the tone of the dressing room and the club for the next decade and up to now.
At the time you had some gems coming in but there was nobody there to turn them into the stalwarts, lion hearts of the past. Players with potential like Rosicky (granted he had his injuries), Walcott, Hleb, Clichy, Sagna, Song who could and should've been the next generation to carry on that mentality. But instead there was a vacuum there without the seasoned professionals to guide them, and something rotting at the centre of it all with players who were either too arrogant or too soft for their own good, like Fabregas, Flamini, Nasri, Eboue (damn good rb but an arsehole).
And you've never recovered since. The players I see coming into Arsenal are clones of the above, and those coming through your youth have no leaders to look up to like those I mentioned right at the start. This isn't about Arteta on his own, it's about the identity of the club. A big part of that is set by the manager but it's also about your player recruitment. Until that changes, this will continue and you'll struggle to compete for the league (fck Top 4 your standard should be the league).
There's no wum in any of this, I may not have all my facts straight, and I don't claim to know your club better than you, but I'm saying it as someone on the outside looking in who knew Arsenal close up and personal, enjoyed and respected the rivalry, many of your players, who's seen enough over the past 20+ years to see the change.