I never once said he was the only problem, I'm aware of the other issues, but realistically he was the only one that could be removed and replaced, sadly those employed to find a replacement weren't willing to do what it takes to bring in a top/proven manager, instead they brought Emery in, who was a better choice than Arteta someone who had never managed a game in his life (that was the only other choice right?) and on paper perhaps to those who didn't know too much about his career looked like a decent 2nd tier choice, but hearing the noises from fans of previous clubs and some of the events in his career perhaps it's a bit clearer he was unlikely to be the right fit.
To go through an entire season without an away with at Sevilla, never progress in the CL and always ending up in the EL and having fans calling him negative and not wanting back, as well as his relative failure at PSG where he was outdone by Monaco despite having the riches of PSG behind him maybe should have been things those employing him had considered before doing so, I do think the bigger issue is that he is a weak manager, Neymar showed this at PSG and his time at Arsenal also shows this with the fallouts and how he's been made to look bad by his own players.