Those playing long term and manage to make their overall PnL in positive is very rare but possible.
The real winners are those who can maintain a healthy bankroll while gambling. No one can 100% beat the casino, but maintaining a manageable bankroll is a win even that isn't a financial. Maintaining a positive outlook is possible, but as you said, it's rare and difficult. So, when we can control our emotions while gambling, we actually win personally and psychologically, not materially.