Putting aside how they're playing as I don't watch their games, when I look at the table Arsenal are exactly where I'd expect them to be. I wouldn't expect them to achieve Top 3 - Chelsea have enormous resources, Liverpool have one of the world's best managers, City have both. Really we should be up there as well, and we had been for a couple of seasons before this year. With us being off the pace, you'd expect Arsenal and Tottenham to be scrapping for 4th, which is exactly what's happening. In fact, 3rd - 6th this season are looking likely to shape up almost identically to how they did in 2018/9 when Emery was at Arsenal and we were in the Mourinho/Ole season.
3rd currently: Chelsea, 70 points (max. 76)
3rd in 18/19: Chelsea 72 points
4th currently: Tottenham, 69 points (max. 72)
4th in 18/19: Tottenham, 71 points
5th currently: Arsenal, 66 points (max. 69)
5th in 18/19: Arsenal, 70 points
6th currently: Us, 58 points (max. 61)
6th in 18/19: Us, 66 points.
As it is, I think Arteta is plodding along quite reasonably. Spurs having Kane and Son skews things as usually neither or Arsenal would have hope of affording anyone that good, so I'd expect them to edge Arsenal out. If he was doing brilliantly Arteta would probably have found a way of overcoming that and nailing down that 4th spot in a season like this. If we was doing awfully I'd expect Arsenal to be around where we are this year.