The situation at Milan is very similar to Man Utd, both fallen giants so far away from their glory days. Football goes in cycles though, I’m confident they’ll both return to glory one day. It might take 10-15 years but they’ll both be back.
I think we're seeing the end of an era with this two teams, AC Milan have been elusive when the big teams compete for trophies for so many years now, United now are following that same trend with the years going by.
When a team falls from glory, it's very difficult to rise again, check all the teams this has happened to, while they are struggling to get back to the elite, the other top teams and getting stronger and stronger and drifting farther away from their level, just look at City and man.u for instance, city are miles away from united at the moment and it looks impossible for the gap to be closed.
But since city closed theirs when they were doing the chasing years back, united can likewise bounce back.