No way. He's improved the team massively so we can compete hopefully to the last day. And the ceiling of Arsenal is very high given the youth of our key players, the fact that there's a once in a generation wonderkid coming through who may break into the team next season, and that with a ninja striker up front we'd be more clinical.
Doesn't mean we overtake City as you'll improve as well, but we are going blow for blow with the best team in the world and the best coach in the world.
We'll be more experienced in the CL next year as well. If Arteta left who else would we be able to get in that's better? It's not like Pep would take the job. The other supermanagers are Klopp and Ancelotti. After those guys Arteta is on par with who is left and he's still early 40s and learning fast.
Like I've said before, we'll be competing with City for prizes for the next 4 or 5 years. Doesn't mean we'll win them of course, but on the flip side at least you'll not need to worry about your team bus getting smashed up by your title rivals before a crunch match. Every cloud.