Bukayo Saka, a 20 year old winger and possibly the biggest talent to ever come through our academy, clearly had the trust of Arteta from day one. He's gone through several dips in form since breaking through but overall has managed to keep his starting berth, and we're reaping the benefits of his staying in the fold.
Pepe, international winger and record signing, never got that chance. Whenever he's had a poor performance, he was benched by any of Saka, ESR, Martinelli or fucking Willian. Even when he's had good performances he was in and out of the starting XI.
Not like this issue is exclusive to Pepe either, ESR was one of our more important players during our good run when he was regularly starting and arguably saved Arteta's job towards the end of 20/21. When his game time dried up so did the goals, he was arguably the worst player in the whole squad in the last few months of the season.
Your point is still "insanely simplifying", or to be more accurate you're mistaking cause and effect.