I think that is the core of the problem, you have no seniority of leadership at all, there is noone who could rightfully be regarded as the boss, as someone who has the ultimate responsibility and takes decisions for the club. (Or who is it? Vinai what's his name? Some US-American rich kid called Chad Kroenke?)
They're all new, they all don't exactly know what they're doing, they are all dependent on each other to work out, because none of them can point at the other and say "you are not doing a well enough job". Mertesacker too, why the hell does he have any say in how the club is run?
None of them, neither Arteta nor Mertesacker, and Edu not really either, have the record and seniority that would suggest they can provide the required level of leadership, experience, and expertise.
You don't win anything with kids, and your club is run by kids. I think it's pretty scary.