The laws of probability would dictate that if a gambler keeps gambling indefinitely then they will lose in the end. I agree that if someone gets into profit and stops then they will make a gain - but how many gamblers have the discipline to stop?
I have never lost a bet yet. I don’t do it. On the basis that the bookie will always win in the end, any gambler must lose in the end. The number of adverts for betting on TV and around football in particular really pisses me off.