Mathematics guarantees that when you bet on infinitely, a time comes when you lose your bankroll.
You cannot win in the long run, because if you win, you are to play again.... till you lose.
But there is no infinity in reality.
In the finite 75 years we live, this scenario I described is totally possible, so much that it could have already happened.
There are millions of casinos worldwide, the odds of this happening is pretty likely in one of them, and it's so strange that people wouldnt even know if its true or not.
If you put 1 million gamblers in front of a slot machine with a 1 million $ bankroll. And for easyness sake have a 0.5% house edge, and let them gamble 1 year straight, every day for 5-6 hours.
I guarantee you that a few gamblers will come out net profitable at the end of the year, it's just inevitable.