Why does arsenal find it hard to compete for domestic trophies 🏆?

Since the appointment of Arteta, the team has struggled with cup competitions. I believe that one reason for this is the rigidity of the manager in terms of tactics and team selection. He doesn't mind using the same 11 for every game as long as they are fit. Cup football is very tactical. Failure to try new things could be and has been catastrophic during his time at Arsenal. Its worrying. Beginning to look like Arsenal can't win any trophy with Mikel. The performances don't suggest that but the results do.

Maybe he has done his best bringing the team to where they are today

He is a manager that doesn't really rotate his team this may be an issue when trying to sign a quality player who might be on the bench

Yes... he's done a remarkable job... but I think he'd flourish more if he had more quality on the bench