When there is a high jackpot, it almost is a break even proposition.[1] Of course this is not zero-sum in the medium term because this situation only occurs because it was not won previous weeks. It takes a jackpot of around $120m to be 'fair' (on the powerball lottery).
That ignores taxes and multiple winners. The Megamillions jackpot hit 640 million and it still had negative expected value. There happened to only be 3 winners, but there could have easily been far more than that.
PS: Powerball tickets also cost 2$ now which means you need a larger jackpot to break even.
1. http://users.stat.umn.edu/~geyer/lottery/