I agree with your idea that Arsenal problem is not about having wrong players but they are thinking how they finish season. Finishing second twice recently shows team is really good and Mikel Arteta has built strong squad that can compete. However their tendency to let rivals catch up late in season is key. This could be due to pressure or not changing tactics enough or just needing more experience in tight title races. To finally win Premier League.Arsenal needs to fix this habit by becoming mentally tougher and rotating players better and and learning from past close calls. Talent is there they just need to perform consistently in crucial moments.
Arteta knew what he and the team needed most but he was not given enough money for purchasing a world class striker. This will continue as their main priority this summer, when they have to find a very quality striker who can score 20 or 30 goals a season for them. Arsenal through latest seasons already shown that they are strong enough to compete for titles but they lacked of a goal productive striker, who can help them getting more points for becoming champion.
When Sir Alex Ferguson was coaching Manchester United he made decision on the player he wants and don't want and that made him coach the club very well, since he retired till date Manchester United have not stand well, I wish Manchester United will have a new owner so a lot of things will change, right now let the management allow the current coach decide who to buy and sell so the club can move forward because if they continue like this next season they will be relegated and that will be very bad.
With Sir Alex Ferguson, Manchester United could win Premier League titles by uniting their team together and maximizing performances of normal players in their club. After era of Sir Alex, other coaches did not have that power, similar trust from the club's board members and they had to deal with a new era of players who can kick head coaches out very easily.
Manchester United have tried to chance since Solskajer but they only shown strong determination with Ten Hag seasons ago. Unfortunately, Ten Hag even was given full trust and support from the club, failed with his mission in Old Trafford. Now it's time for Ruben Amorim and no signal that Manchester United will not give him similar trust and support like what Ten Hag received. This young head coach has to show off his management quality next season, at least finishing it wtih an acceptable rank at least in top six.