Another way of looking at it would be,
United finishing 5th and near to their 4th position the season before this one.
City have regressed in their League position but they have advanced to the CL semis.
Arsenal finished 2nd last season and definitely improved on their league standing.
Chelsea on the other hand got a 10th place position, got knocked out of CL round of 16 without even putting up a fight against a team that city knocked out. Got single-handedly knocked out of FA cup by Lukaku who has yet again shown that he is a special player. Also, Chelsea dont have any european competition to play in compared to 3 out of those 4 teams and I am pretty sure, we would find Lukaku in a team with atleast EL football, very soon.
And we did win the league the season before last, but was it worth the massive set-back to the club overall? Not for me.