Talking about "traditional" sports gambling rather than prediction markets: how do we account for the heavy restrictions they place on "sharps" (consistent winners)? If a game can be won through application of skill, but winning through application of skill causes you to be effectively banned, then the game cannot be won through application of skill.
They don't mind a few with skill so long as those people don't win too often and they brag about their winnings to others who then think they have skill.
of course if you had the skill to win big why would you not make that your job thus making too much.
There is an entire category of casino games where the house is a player. These are called house-banked games and they include most of what you imagine when you think of a casino floor: blackjack, roulette, craps, slots, etc.
But even in player-banked games like poker, the house is an agent participating in the game through the dealer. They can still exercise their right to free association and not play with you.
A corrected analogy would be Nintendo banning you from Mario Kart Online for suspected cheating. Yes, Nintendo isn't playing, but they still have that authority as the facilitator.
