A bet absolutely can produce value, it just can't produce money.
Consider a bet on a dice roll which is done solely for the purpose of entertainment (unlike bets on events which reveal information). The gambler gains utility from playing the game which presumably exceeds the utility lost due to the house take (otherwise, why bother playing).
Consider a simpler game: Street Fighter III. The house take is two quarters and you've got no chance of winning any money. Nevertheless, value is created since the players have a good time playing.
Yes, I agree that the company running the gambling is selling entertainment.
But the word 'bet' is wrong when applied indiscriminately to shares and derivatives. The way nazgulnarsil is using the word 'bet' marks a profound confusion about betting and stock markets. The whole point of stock markets is that the 'pot' can increase. With gambling the 'pot' decreases - in line with the entertainment value gained by the participants.
Consider a bet on a dice roll which is done solely for the purpose of entertainment (unlike bets on events which reveal information). The gambler gains utility from playing the game which presumably exceeds the utility lost due to the house take (otherwise, why bother playing).
Consider a simpler game: Street Fighter III. The house take is two quarters and you've got no chance of winning any money. Nevertheless, value is created since the players have a good time playing.