Yup, once the machine is maxed out it is going to pay out. It might take 500 in before it pays out or it might take 2500 in before it pays out. So you wait and hope nobody hits it before you give it a go. Now I am talking about bar machines not Vegas machines but I’d bet they are similar.
I would imagine they work the same way. Tho with casinos they’re open 24 hours, so it would be harder to wait til later in the day/end of the day.
But the general principle is that when it’s taken x amount of dollars it pays off - that is, it’s not just set to hit jackpot at random times?