This is obvious. Everybody DOES lose, because of the fact that there's a house edge and you're not infinitely wealthy. It's simple statistics, really.
It's only obvious if you gamble constantly and incessantly as mathematically you will eventually hit a unrecoverable losing streak due to lack of funds but many gamblers can stay in profit without bankrupting themselves so its not a gurantee for the small percent that are really lucky or have the relevant skills to make good bets. I think casino gambling is also much easier to lose on then say sports betting. Casino games are usually ramdom whereas sports you can use educated guesses.