If you gamble everyday then yes you will lose in the long run. There's no denying in that. The house will always be the more profitable party in gambling. This is why it's best to gamble just for entertainment and when you can afford it.
And that is also why casino is so profitable. Real life casino is setting up one after another one in different parts of the world and they can earn plenty of money to be taxed heavily too.
Regardless it is online casino or not as long as you are gambling then you are destined to lose in the long run. Those people who are winning great amount in it are the more prone to it.
Because they will not care on how much they are able to lose within the day, as long as they had something to use and bet in their pocket they would do.
Only wise gamblers will not fall into losing in the long run, they may fall at first but you can learn from it.