Originally Posted by
go_buccos
Your intuitions are both right and wrong in this case.
First off, where you're wrong is regarding cash availability. The casino absolutely has the cash on hand to pay it. By law, at least in every U.S. commercial jurisdiction that I'm aware of, the casino must keep enough cash on hand to cover every single max slot payout and every table game chip in their inventory. This obviously adds up, at least at the larger stores, to tens of millions of dollars or more.
Where you're correct is regarding the huge seven figure-type slot jackpots. Most of these are known as "wide-area progressives," where more than one casino within a jurisdiction has a certain type of machine linked to the same top award. In these cases, IGT (or whoever) IS on the hook for the top award. Obviously, they also share in the revenue generated from these machines with the host casino.
Also, with most of these life-changing money type jackpots, the winner has the option to take the full amount in an annuity, or take a lesser "lump sum" cash payout immediately. Similar to how Powerball works.
Hope this helps!