Arsenal spend a lot of money on transfers and they are progressing well, but you are right in saying that they are left without a trophy, and this is the main indicator of a team's success. I understand that Arteta has done a lot for Arsenal, he was given a chance and he took advantage of it, but if this continues, then Arsenal will be forced to change something, if Arteta is a coach who cannot win a single title, then he will not be able to stay for long in the coach's place. Manchester United have a different situation, they have trophies but they play worse, so they need balance in everything.
I feel like there isn't really a situation where we can't focus on how much money they are spending, there are other teams who spend even more and do not get as much result as Arsenal does. This should not be the thing that we blame them for, if you want to have a good team then you are going to end up with spending some money, look at who won the league, Manchester City, can we say that they do not spend much?
There are teams that spend even more than City to be fair, but still it doesn't mean City doesn't build a great squad. We should be considering the fact that we are going to end up with Arsenal finally doing better but it will take a bit of time to build that legacy, it will be maybe this season but it could be something different.
After all, the problem or comparison is about winning trophies, Arteta has succeeded in improving Arsenal's quality over at least the last two or three seasons. But in reality, Arteta still failed to make Arsenal win a trophy. Meanwhile regarding Manchester United, even though Manchester United's performance or quality is not as good as Arsenal's, but in reality Manchester United still managed to get a trophy even though they only got the FA Cup trophy. Thus,if Arteta continues to fail to bring Arsenal to a trophy, then the question is whether Arsenal will still retain Arteta or not. But I personally believe that Arsenal will still give Arteta their trust and opportunity, even though in reality it will still take a long time for Arteta to get Arsenal a trophy.