Some gamblers do win but only few times and after they win they lose it again which means all gamblers lose money in the long run.I agree only the casinos which have a fixed house edge win in the long run.The casino is created with the sole intention to make money to the owners in the long term.But yes some gamblers do actually win and lately I have won some money in slot machines which I am sure I will lose them soon.
This is the thing, on the short term it is possible to obtain some profits out of gambling since the house edge did not had the opportunity to tilt the results in favour of the casino, but the longer you play a game with a negative EV the higher the certainty that you will lose money over the long term, this is confusing to players since they do not really understand the odds of the games but it is the truth, so if you do not really have any way to change the EV of the games then you should expect to become a loser over the long term.