Vegas always gets their cut as you point out. You need to reliably win 52.5% of the time to beat the bet $110 to win $100 edge.
In general, betting schemes tend to stop working in the long term, but can have large gains in the short term [1]. We created this example to encourage people to think about model tuning in the applications where they are domain experts and how it could benefit them (and hopefully the world in return).
Kind of sort of. The way the Vegas books are made are to make consistent profit while mitigating as much risk as possible. Which means, although not quite like the zero-sum markets which exist in securities, you still have to have more or less need the scales to weigh out.
What you can capitalize on is human emotional -- i.e. the Dallas Cowboys are notorious for being bet heavily in favor of, even if statistically they're not going to win because of sentiment or what-not. Let's say statistically they're underdogs by 10.5 pts. Let's not talk about covering the spread or parlays or anything complicated - just pretend the market is limited to solely 'bet to win'. If it were the Bengals as the underdog at the same 10.5 against the Raiders (just teams where the fan base doesn't skew the book), you might see -170 to win 100 , and conversely if the Raiders win, it might be bet +140 to win 100. (I haven't bet on sports in years, so I'm not sure how the actual numerics work out). Either way, as underdogs, since so many people will be betting on the Cowboys even though they're predicted to lose by greater than 10.5, the line will only be at -120 due to the volume of bets being taken. Vegas has to move the line accordingly to adjust for the contingency that the Cowboys actually do win, paying out 170 on those upsets could bankrupt them.
Being successful at fantasy sports is probably a lot easier than being successful at trading crude oil, because John and his buddies will all throw down 40 bucks each for the Cowboys to win even though the odds are heavily skewed against them. And unlike in Vegas, you can consistently be profitable and not get black-listed. (Counting cards should be legal if you are not colluding with anyone, but I digress).
Interestingly enough, 'betting schemes' might not work for the average player, but there's a reason why the same 10 players make it to the final table of the World Series of Poker. In fact that's how those daily betting fantasy poker gaming sites are in business. It doesn't violate the unlawful gaming act because games like poker[1] and fantasy football clearly have consistent winners and losers, even though those attributes often can't be quantified via any sort of metric, it's enough for judges to rule that certain forms of gambling are games of skill.
[1] http://www.npr.org/2012/08/22/159833145/judge-rules-poker-is... I've seen the same ruling at the highest circuit of tons of states, and I'm guessing it must be federally recognized as the fantasy daily line-up games are making literally billions off it now.
In general, betting schemes tend to stop working in the long term, but can have large gains in the short term [1]. We created this example to encourage people to think about model tuning in the applications where they are domain experts and how it could benefit them (and hopefully the world in return).
[1]: http://www.wsj.com/articles/a-fantasy-sports-wizards-winning...