Hey I'm Nicky Numbers, I'm a professional poker player, and maybe the most common question I get asked is: How much of poker is luck versus skill? Well, that answer to that really depends on the sample size. If you just play one hand of poker, it's going to primarily be luck that drives the outcome of the hand. Just one session of cash game poker is going to be largely luck. One tournament hand or one tournament, tremendous amounts of luck. However, the more hands you play, the less luck there is.
As the number of hands approaches infinity, luck approaches zero. If you play tens of thousands of cash game hands, or thousands of tournaments, and you're a good poker player, you will win in the long run. Poker is a pure skill and the reason it's beatable in the long run is because the house, the poker room or the casino, only takes a very small amount out of each pot and they're not a player.
You're not playing against the house like you would be in craps or roulette, where if you play frequently enough, they're guaranteed to win. In poker you're playing against other players and the house is basically just charging you an hourly amount to sit at the table. This amount comes out in the form of rake, which they take a small percentage from each pot or they take an upfront vig for a poker tournament. So for example you might play a poker tournament that's $120, where $20 of it is just going to the house and $100 is going to the prize pool. Unless the rake is too high, which it will rarely be in a casino or a poker room, then the games are going to be beatable.
However, you do have to be careful when you're playing in home games or private games, because it's not uncommon for those games to have enormous rakes. Something like 10% of the pot with no cap might well be an unbeatable game for most if not all poker players. The more poker that's played, the more the cream will rise to the top. Play enough poker, and if you're a very good player, you will win in the long run.