Certainly in the short run, poker players can make money. But if you read the stories of the top tier players, they often have bad runs where they lose everything. I read an interview recently where a top tier player was asked if he thought it was possible to live the life of a poker player and never go broke. He said he didn’t think so. He is married to another poker pro, by the way.
Of course many of the top tier poker players are just degenerate gamblers when it comes down to it. There are many stories of players using their heads to win oodles of money in poker and then losing it on sports betting, proposition bets, or other casino games. TJ Cloutier has won millions at poker and lost as much at craps, and is notorious for begging stakes from everyone he knows. Mike Matusow won a two million dollar prize and was broke before he left the casino. He couldn’t pay taxes on the winnings and did time. Barry Greenstein was asked to donate to some charity and he wrote out a ten thousand dollar check. The solicitor asked if he could afford it and Barry said, “I’m already so far in debt, what’s another ten thousand matter.”
The answer is clearer for black jack: no, they won’t let you win. In casinos you get banned if you win. There’s no presumption of innocence around card counting; if you win, they don’t want your business. I’m sure online that they tweak the rules so that no one can win. Perhaps they reshuffle every hand?