If you dive into the article you'll see where the big winners, that they call "sharps" have found ways around this, like exploiting differences between multiple books, finding arbitrages and betting heavily and quickly in changing situations before the market has a chance to settle. I play a browser game called Torn that has a play money sportsbook and I've absolutely identified scenarios where either side of a straight win/loss bet was paying out positive. What this effectively meant is that I could bet the same amount on each team in the match to win and be guaranteed to walk away with money.