Interesting. Although Keno's house edge is huge, it may not be worth the floor space devoted to it. The game is fairly slow and certainly never looked that popular to me. Unless a casino is willing to pay several keno runners to drum up business in their restaurants, it probably isn't a big money maker.
I think the disappearance of Keno has been an ongoing process. It seems that most of their business was not done in the Keno parlor but through runners in the restaurants. I would guess that the overhead finally got too much and the casinos saw greater profit potential for the space that the Keno operation was taking up.
They still exist I know that Harrahs and Rio have Keno. Riveria (haven't been there in years) use to have Keno. A lot of the Downtown properties have Keno (Plaza for one). Most of the "Stations Casinos" have keno. (Palace Station for one). Someone told me that, "In case of a hurricane, go to the Keno room because nothing ever hits there":laugh: