~snip~
Yes I agree with your idea that gambling is more than just a fun game, there is something they are after and maybe we can already conclude here that they are after a return on the money they put in, or I mean wanting a bigger amount than the capital money they brought. On the other hand, if they're just there for the fun of it then aren't there plenty of other things they can do without the possibility of risk such as playing online games for example? Obviously, and gambling is someone's choice to pursue something that is basically not easy to achieve.
As you said that if fun is the main priority then I think people will prefer to gamble on a demo account which certainly does not require real money capital and only requires free time, so your assumption is quite reasonable in my opinion and it can be a strong reason why people come to gamble.
Yeah, there is a small amount of fun that people get when playing the free games, but that's quickly gone and the interest of actually making real money starts.
At the end of the day it is the idea of making money that is the addictive ingredient, the games, lights, sounds, etc, are all there to help, but they are not the main thing.