I don't really have an Idea on how this works but I believe it is going to cost you a lot of money because after creating and programing everything you will have to test run everything and then the best way to make people know about your game and start playing it is through promoters, once you are done with everything you will get a good promoter that will promote your game by creating awareness and advertising it and if the game is interesting then you are settled but note that the promoter will charge you high because he or she knows what you stand to gain after everything.
I do not think it needs that much money, since he is the developer himself, all the testing and everything can be run through a script. Unless he wanted to be a casino himself, all he needed was to offer the games to the casino by writing them letters and proposals. And by giving them the data and testing analysis, it is up to the casino whether they will acquire it or not, just like what @Solosanz stated, if they get a liking on your game, they will definitely inquire about it.