fisheater
Contributor
According to an article I was required to read when I got my first professional training, the model for the MSD was Boy Scouts. If you are a first class Scout and wish to advance to next rank--Star Scout, you need to acquire 5 merit badges.
Back when this was first done, all the merit badges (er, specialty certifications) that were available actually did make you a better diver. If you got 5 badges, you got close to all that were available. Today it is possible to get 5 such badges without actually going in the water all that much.
If that's the case, PADI missed the whole point of the Eagle rank. It's not "get 21 merit badges and here you are." You also have to demonstrate leadership in your troop, as well as plan and execute a service project involving many volunteer man-hours, not to mention the whole upstanding character and all that.