The casino is being run by greedy management who I am sure is under great pressure to keep Wynn in the black. In my opinion, it is beyond the meager payout.
Of course one has to bear in mind that Wynn is a going concern - a business - and a business needs to turn a profit. Of course there will always be the odd jackpot or handsome payout here and there through the day. Only small blocks throughout the week seem to offer ANY chance of winning.
The casino actively seems to manage when and how much a person can win. As a player who has visited with enough regularity and at many many different times during the week and during the day, I can tell you without any doubt that the overall majority of players leave the casino losers. As echoed by COUNTLESS others who have bemoaned the ridiculously tight and poorly paying slot machines, I am afraid I also try to warn others off from wasting their hard earned dollars at the Everett casino and resort.