Some bookmakers (Pinnacle, Sbobet, ibcbet etc.) do just that and their odds are controlled by the amount of money being bet on either side of the handicap, but

Some bookmakers (Pinnacle, Sbobet, ibcbet etc.) do just that and their odds are controlled by the amount of money being bet on either side of the handicap, but it's a completely different model and most bookmakers don't have the liquidity to do this.