[placidpanda]

Sportsbooks make money by taking bets on both sides of a game and offering odds that work in their favor. For example, even on an "even money" bet, you might have to bet $105 to win $100. The more one-sided a game seems, the bigger the gap between the odds on either side because the sportsbook is trying to manage its risk. As people place bets, they adjust the odds to balance the action. The sportsbook isn't banking on you being wrong—they want enough bets on both sides so they win no matter what. The difference between the odds is basically their "fee."

As a professional bettor, you're not really outsmarting the sportsbook—you’re trying to outsmart the public. The key is finding moments where the crowd is wrong enough that betting the other side makes sense, even with the sportsbook’s fees. That means you’ll often skip betting when the odds are pretty accurate.

Most sportsbooks will limit how much you can bet if you're too successful, but they usually won’t ban you outright.

[pclmulqdq]

Many sportsbooks actually do not run that way. The name "sportsbook" implies that they do, but that is an older style of betting that has fallen out of favor. Modern sports books usually use fixed odds set by an oddsmaker (in modern times, algorithms set by the oddsmaker), but those odds are allowed to float with the probability of the outcome changing. I believe they take supply and demand into account, but you actually are betting against the house. That prevents the kind of trading against the crowd that would be normally viable.

The Hong Kong horse race track was a famous example of market-priced bets where the book was run the way you said and the crowd was exploitable in the way you are suggesting. It was one of the last books to work that way.

[placidpanda]

I can see the misunderstanding, but I was not actually describing parimutuel betting (horseracing). In parimutuel betting the odds continue to change up until the race even once you've placed your bet ensuring that the payout is always the total amount wagered less a fee kept by the house.

Sportsbooks will open lines intelligently, but they absolutely do move the line in response to market forces in an attempt to balance money on both sides, because when the money is balanced, they are guaranteed profit.

It's true that when you make a sports wager, the house is paying you out of their wallet. It's also true that they employ a lot of energy and expertise in order to open the betting at accurate odds. However, no corporate, end user facing sportsbook is themselves fading action on one side of the match intentionally. They aggressively try to balance money on both sides so they can guarantee a profit.