I'm curious, what do you base this on? Arsenal have a pretty young squad with several of their key players entering their prime. Rice, Ødegaard, Saka, Martinelli, Saliba, and Gabriel Magalhaes all have at least five years left at their highest level, barring injury. Meanwhile, Liverpool are losing Klopp, and City will eventually lose Pep too, while Chelsea and Man United are scrambling to find any kind of consistency.
I think Arteta is the ultimate tool, but I'd be extremely optimistic about the future as an Arsenal fan.