The tracks in fact do get a "takout" on each bet and the remaining money goes into the wagering pool, but remember they have to pay the purse of the race out of that takeout money as well as maintain the track and wagering areas, etc....
Alot of states that allow slot machines only allow them at race tracks so it is OK to lose money with the horses if you can rake it in on the slot action, which they do. Here in Pennsylvania slots are a hot issue right now and again if legalized they will only be allowed at race tracks with the possible exception of 2 "slot houses" one each in Pittsburgh and Philladelphia, God forbid we actually allow table games as well, the Amish may move out and take their, well, whatever it is they contribute with them
Penguinfan