I don't think gambling is at all like paying a set price for a ticket and having a pretty good idea of how long the entertainment will last. If "gambling" means making a series of short-term bets for entertainment value, you don't have any clear idea how long you'll be entertained for or how much it will cost.
People will show up at a casino with let's say, $200 and a debit card, and expect that they'll be able to spend $50, be entertained for 2 hours, and then just leave… while secretly hoping that they'll actually leave with more than they came with.
Then they burn through their $50 in half an hour, and dip into their remaining stash in order to keep playing. OR they triple their money in half an hour and feel such a rush that they want to keep playing with more money. Then, repeat repeat repeat.
Generally you can gain a pretty good understanding of how long the entertainment will last. Maybe not down to the millisecond, but you know a spin on the one arm bandit won't take hours. It will give on the order of seconds. Your willingness to give up x is contingent on the perceived entertainment value of those seconds. If you choose to play again, that is an independent event — like deciding to watch a second movie while you are already at the theatre.
> while secretly hoping that they'll actually leave with more than they came with.
Yes, this may be the undefined variable. The dopamine hit of believing you can come home better than you started, with little tastes of the possibility, coupled with loss aversion when it isn't being realized. This is what earlier comments seem to be speaking about, so perhaps, despite your insistence, a consensus was already reached.
People who are really into roulette get a buzz off seeing the wheel spin, hearing the ball bouncing etc.
Probably that comes after the initial addiction to the reward function but it then strongly reinforces it.
I don't think there's an equivalent for paying to watch a movie because the time to payoff (or not) is too long and the sensory experience is too inconsistent to elicit a conditioned place preference.
LLMs on the other hand... the time to payoff is shorter and the experience is consistent every time. It's just lacking the tactile/sensory elements