Machines have a percentage payout over time which is consistent with whatever laws the state says is the percentage payback rate. it is not their prime directive for entering one.
but these people play for the fun and the thrill, not to make a profit. Any outcome cannot be devastating to them because they were prepared for it to go either way. If they come out with more then they are happy, they may have a big win or lose some of it or all of it. Sensible people visit now and again with bankroll they can afford to lose and play for fun. A lot of people earn about a hundred a day in their work. The 100 bucks a day I have picked because its a sort of figure to be able to eek out a living on without the need to work.
If you want to make say $100.00 tax free a day and you live near a casino or in a casino state you have all you need. The first thing I would say is to treat it like a business, your lively-hood.
Most people say the slots are the worst thing to play in the casino. Is it possible to make a living playing very carefully and with great restraint and discipline on the slots.