Summing up our conclusions, it's much better to play in a week with a big jackpot than a small one (duh!) but even in a week with a near record jackpot (second largest in history) the lottery is only almost but not quite a break even proposition.
Mathematically, I agree. Psychologically, many people are paying for the fantasy and it may be what helps them cope with an otherwise pretty tough life. The idea/fantasy that "all this could change one day thanks to the lottery" may very well be worth the ticket price to those people. I'll hold my judgment and not call them suckers on this basis.