There are key reasons why books go broke. Here are some more...
Not a big enough bankroll, and a mixture of greed. They go in with a 200k bankroll, and keep all bets and don't lay off any. They could book 35 dimes on a baseball game, which is almost 20% of their whole bankroll. At 200k bankroll, they should not keep any games for more than 3 or 4 dimes or else they risk of going broke after a bad run. But some books will keep all bets and not dump any out. They are looking for the fast buck and get rich quick, but this always backfires. You need cash to make cash.. deep pockets is big.. and NO greed. I know of many bookies who are also gamblers. They could have already too much on the NYY, and they'll go out and bet the other side for another 5 dimes, because the amount they have is not enough..
You should never have more than 2% (max) of your bankroll on any game or you are asking for trouble. Bookies also book with their hearts a lot and if they like a game, they will lower the price to get action on it and sometimes not even move the number because they are sick and think that just because they love that game, that they know something. NEVER ever should any book handicap a line too much bec they like so and so. If they do like em, fine, but don't move more than 5 cents on a 20 cent line, or more than 2 or 3 cents on a 10 cent line. So bookies should keep the lines accurate and follow the screen if they have to and not keep too much on a game.. And also, when a bookie sees a sharp player who is beating him to every number, alot of bookies have that dumb mentality that they will eventually lose. This is horse shit. Just because they are a bettor, does NOT mean they will lose. They will WIN.. Instead of taking his bets still, they should either lower his limits to very minimal, which will force him to quit, OR, just boot the guy. NO way should any book keep a bettor who is beating him to every number. These bookies just love the action and believe that just bec they are on the other side of the fence, that the vig will catch up to them. They couldn't be more wrong.. But bookies just love to write action, that is why there are a lot of deadbeat bookies out there who will fail and never make it in this business. And it all comes down to one word.. G R E E D..