Depends on what you class as success. MME may not be doing as well as it should be in terms of pax numbers, but there are many other criteria to include. MME has Flight Precision and FRA two very large users of the airport, ok not large aircraft but they do put money and movements through the airport. Then there is the flying schools, ok again not big business but providing a service to all those who want to become pilots. Then you have TNT ok again only a small item but MME is there European maintenance base for the 146. Then you have the Fire School providing an invaluable service again. On top of this MME is used by many airlines for training and just over the past few days Ryanair, Jet2 and Flyglobespan have all been doing circuits.
I believe that too many people put to much emphasis on pax numbers at airports. Yes more often than not it is what counts and is usually what most airports are judged on, but what is a successful airport?