If a gambler says he's never lost money gambling in his life, I'd say he's either gambled only once lor he's lying. No matter how experienced a gambler is in gambling, he will lose his money at least once in his life. Many times it is seen that the discussions about gambling are all fine but unexpected things happen in the middle. I bet quite cautiously on different sports and mostly I bet on the team which has the best chance of winning but sometimes there are many weaker teams beating stronger teams than them but here our experience does not help but here fate is working against us. So agreeing with you, I can say this much that every gambler has lost money by gambling at least once in his life.
Loosing is part of the experience you get as a gambler, you can never gamble at least five ore more times.and not have a loss in between, it's normal but then your experience and logic sometimes may come to your rescue to help you get to recover sometimes later if you have a good strategy.
Sometimes even with the best picks where you have some good level of assurance due to your statistical analysis, the games still happen to turn out a loose especially when it has to do with sports betting that is filled with so many uncertainties, but it's very important you try to control your losses. For a fact every gambler who has Gambled st least more than twice and us still gambling has definitely had a loss regardless of how small or big.