Rankings are the public opinion's approximation of ability and accomplishments.
If Shane Carwin(or better yet Roy Nelson) went 50-0 even with his limited skillset, then he'd be #1 p4p no questions asked.
"I think smoking pot is good for mixed martial artists. It's a new day and age, this is, uh, the year ... Fuck year is it? I don't know, because I've been training and smoking pot like I should..."