Over the years I've noticed a pattern. If there's a "mega draw" coming up, as there is this Friday, the jackpot won't be won in the draws leading up to it.
Same when it's something like Easter or Christmas - it rolls over so there is a big jackpot around the holiday. It's no skin off my nose as I don't do it any more since they added loads of extra numbers and put the ticket price up, but I noticed this pattern years ago, and I really have come to the conclusion that it's a tax on the gullible.