You said we can not win over house in the long run in online casino so I assumed that you are saying we can win long term in real casinos.
If you play smart, you can. Count cards in card games, especially in poker and blackjack. Play alone in the table, so you can know all cards in deck.
Card counting in blackjack is not as effective as many imagined. The house can shuffle the decks more often, or they can ask you to leave and ban you from playing.
Then you should choose the right casino for that. If they don't let you counting then boycott them. Don't play there again and tell everybody your story. They can't ban you for this reason.
All businesses reserve the right to "
refuse service to any customer" and because of this rule they can ban you from playing at their Casino. And you can't do anything about it.
@OP, There are people who make their living through gambling, they're mostly sports gamblers and they get really good at it through a lot of experience and knowledge and they do make profit in long term. So yes it is possible but you will have to take it really seriously and also understand that just because they were able to do it, does not mean you will be able to do it too. So you might end up broke, a Job is generally a better idea.