To be fair, I just got to the end of the article and discovered that it mentioned this paper too...

One aspect that isn't mentioned, is that Benter (and Zeljko Ranogajec, mentioned at the very end) got a large edge over over punters by negotiating large discounts/rebates from the betting pools by providing such large volumes. It's easier to make a profit when you are getting (say) 10% back on your losing bets...

Play the game with the rules you can make, not the rules you think exist...

Disclosure: paraphrasing Sirlin http://www.sirlin.net/ptw/

Pretty big thing to not mention TBH, given the odds are so slim once you take the track's take into account.