What you may not realize is that much of the highly succesful bodybuilder's routines consist of big compound movements that are actually the same whole body exercises used in Cosgrove's program.
It's ridiculous at best to make this kind of generalization. What about the lifter that does deadlifts on back day and then the lifter that does deadlits on leg day?! What is the proper day to perform this exercise on. Bent over rows on back day, or bent over rows on bicep day... both muscles grow with this classic exercise. I guess that kind of throws you off if you're the bobdybuilder doing the ever popular back/chest day in his 4 day split. Would it burst his bubble to tell him that he is isometrically contracting his hams and nailing his biceps on back/chest day?
Have you also considered the fact that any top level bodybuilder may have some good genetics and discipline that may override any weaknesses in 32% of his routine?
What about the bodybuilder that didn't place in the top 5... could he have placed higher by NOT doing that stupid 5 day split?
Whoever said all of these bodybuilders were as strong and athletic as they could be? There are many reasons why Cosgrove and other's are right on target.
I would never train someone seeking general fat loss and "health" with a Weider, Muscle and Fiction type of routine. If the split routine was truly superior for just getting a good body, why wouldn't I and other non-Mickey Mouse, non-ACE certified trainers use it?... Because it's not superior.