Why did the craps dealer cheat?
The house takes a percentage. A casino does not need to cheat.
I'm not saying it is unrealistic. Casinos are not known for being scrupulous. Probably some cheating going on somewhere. I know poker tournament promised winnings are sometimes underpaid. It depends on how many players participate. The house takes a cut and the winner gets what is left as a percentage.
But switching dice?
Why risk the trouble?