Looking through celebrity examples on his website, I wouldn't say he types most of them as EIE. EIE, LSI, SLE, IEI, LIE, ILI and SEE are the most common, and peripheral quadras are almost non existant.
I personally agree that central quadras are more likely to be motivated to become a celebrity (or at least influencial in society) but I think he and Timur take this too far, surely alphas and deltas are motivated by other things than being an anonymous corn farmer on the outskirts of society.