I played many hours at a roulette table using the system of progressive gambling. I came out ahead, and have no reason to think I couldn’t do it forever and come out ahead.
To be fair, it is more boring than any regular work, and I didn’t win very much since I was only winning 1.50 on each spin which I won. I couldn’t just bet more, since in this system, you end up betting exponential amounts to your original bet.
The system is that you play on a 50-50 chance(or 53-47), so I was betting on half the board. Each time you win, you bet again the same amount. Each time you lose, you double, and continue doubling with each loss until you win. Statistically you will win every other roll, but it often goes many times without a win. As long as it never gets to an amount which you are unwilling to bet or to the table limit, you will eventually win and be up another original bet.