Furball
Evil Scotsman
Yeah this is the crux of the issue for me. Aubameyang excepted, I doubt any of Arsenal's players would be coveted by teams challenging for the top 4 (hell, Chelsea released Willian and basically gave away David Luiz), which means there's only really so much you can reasonably expect Arteta to get from them. He's probably not helped himself in terms of expectations by winning a trophy so early, although even that was done mostly on the back of being well organised defensively and some individual brilliance on the part of Aubameyang.Nuno can't coach an attack either, I'd say you'd look pretty similar under him as under Arteta. Ancelotti was exactly the wrong type of coach for where Arsenal were. Allegri, meh. He's a good tactician but he tends to leave clubs in worse shape than they were when he arrived. Again, not what Arsenal needed.
Arteta was always likely to "fail" because he inherited a mid-table squad with expectations of a top four challenge. But he had good upside and made sense given the club's situation at the time. Just because it might not work out doesn't mean he was the wrong choice.