In addition to what others have stated, many casinos have both minimums and caps on maximum bets. This means that you can only do this so many times. You WILL eventually lose it all.

I managed to do this once with an electronic machine and made money once because it had a minimum bet of $1.00, no maximum, and apparently wasn’t rigged. I made high 4 figures before I got bored. The next time I came in, the minimum was upped, a maximum was added, and the game was clearly changed to favor the house.