'Expected utility' is a familiar concept from decision theory, a mathematical approach to rational decision making. Read up on it, instead of saying 'economics is bullshit anyways' which is stupid.
Usually, people argue that partaking in lotteries is irrational because the expected utility of purchasing a ticket is less than one. In this case--when the powerball hasn't been paid out in a while and the jackpot keeps growing--that argument no longer holds up. That's all I said.
But you're right, there are other factors worth taking into account. One is opportunity cost. But for purchasing a $1 ticket, that doesn't apply really. Another (and more relevant one) is that people are risk-averse.
For instance, if I had a million dollars and I could buy for that money 2 tickets in a 3-ticket lottery where the pay-out is 2 million (effectively, giving me a 66% shot at 2 million), I wouldn't do it. Expected utility is more than one, but I still wouldn't do it, partly because our lives are finite and as a result people are risk-averse.