It might be something we should treat more like smoking.
- Require a disclosure of the EV of each bet as the user is placing it. E.g.: Expected loss $5.
- Ad targeting restrictions.
But variance, not expectation, is where casinos get their edge. The “Gambler’s ruin”[0] demonstrates that even in a fair game the Casino will win due to their effectively infinite bankroll compared to the player.
You can also simulate this yourself in code: have multiple players with small bankrolls play a game with positive EV but very high variance. You’ll find that the majority of players still lose all their money to the casino.
You can also see this intuitively: Imagine a game with a 1 in a million chance to win 2 million dollars, but each player only has a $10 bankroll. You can easily see that a thousand people could play this game and the house would still come out ahead despite the EV being very much in the players favor.