I don't see much difference between Wangersky's logic and the VOCM callers who, before daring to voice anything beyond the party line, always preface their comments with an obligatory genuflection towards DW.
Wangersky's assumption about the causal link between personal gain and corruption is not his only faulty premise. He seems to assume that DW is endowed with special, super abilities -- hence the vapid Hockey Phenom metaphor -- ergo, DW should have been able to use those amazing abilities to break with the errors of his inferior, corruption-loving predecessors. Just because DW was a wealthy lawyer/businessman does not mean that he was on the verge of being a successful premier in 2003.
It's like assuming that a wealthy plumber would be a great psychiatrist. Governing in a democracy is, in important respects, radically different from ruling a law office. And those differences may very well lie at the heart of the "disappointment" that seems to perplex Wangersky.
It's a sign of how far down the rabbit hole we've gone that poor old Lord Acton has been turned on his head. In this dystopian world, the maxim seems to be that power corrupts but absolute power does not.
And, for the record, none of DW's less-wealthy, more poll-challenged predecessors got rich from corruption during their premiership. Moores and Tobin may be the exceptions, but their wealth came from contacts after they left office.