They're not, generally, but if the stars align correctly, nobody will win the jackpot until it's gotten so large that buying every possible combination will - i

They're not, generally, but if the stars align correctly, nobody will win the jackpot until it's gotten so large that buying every possible combination will - if you're the only winner - pay you more than the base odds. But then you're betting that you will have the only winning ticket. I'll usually buy a few tickets if it hits that point. Cheap fantasy.