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, Im confident theyll both return to glory one day. It might take 10-15 years but theyll both be back.
I don't think that Milan and Man Utd are on the same situation.
Milan is lacking both players and a talented manager. In other words they need to rebuild the team from the beginning.
Man Utd has a lot of skilled players and a good manager, but still they are unable to get results.