Bookmakers can always lay the odds so that there’s equal money on each side. Then they’re just taking a 10% rake with zero risk. If they start getting killed by pros they’ll just move to the low risk strategy.
> Bookmakers can always lay the odds so that there’s equal money on each side
No they can't. Large ones can, but the small ones sometimes cannot because they have to match the large ones but in a smaller pool. If everyone knows which team is going to win, diehard fans of the losing team will still bet on their team - large players capture that in their odds and break even. Small players don't have the same mix of customers and so will have to take that loss because they need to compete with the large ones.
Of course overall the small players balance enough the 10% rake from less sure games over the years to make a lot of money but they can still lose 6 figures on some individual games. Small players are less a target for the pros (if only because they know their customer better and so won't accept the pros in the first place).
Remember the small players are often running an illegal operation. They need their reputation of paying out so that customers don't go elsewhere to even turn them in.
Also, for what it's worth, the idea that betting lines and odds are set to make "equal money on both sides" is a very simplistic and often ignorant talking point. It is quite possible if not common, especially on big games like the SB, for the books to have significant exposure to one side.
Making betting lines is a crazy complex mix of the house essentially betting on an outcome themselves, tempered by a limit to exposure/liability as well as the need to keep lines in basic accordance with other linemakers.
The issue is the big players publish their spread. You have to at worst match them or everyone sends their money to the big players. You can beat them but not do worse. For bets on the local little league you can set your own spread but the big money is national (and international), sports where you have competition and so need to watch what they do. As a small agent you shouldn't bother calculating spread on the big games just match the large players.
I wonder if street bookies make money “for someone” by somehow bringing lending in house. It would be the pair of activities that would be profitable. But they wouldn’t have to be that good at bookmaking.