Don't take my explanation as gospel, but I'm positive that the room rate is negotiated a year in advance with the host hotel and is written into the contract.

If hotels have excess room inventory, they are free to quote any rate they wish to the public but the rate that was negotiated for the annual convention is guaranteed (only for the block number of rooms that have been set aside for our group). BTW: $79 per night on a weekend is not a bad price for a major strip property.

Can you find cheaper? I'm sure you can. But the inconvenience of traveling back and forth from other hotels to the host site in the summer desert heat must be considered. It's nice to be able to just go upstairs to refresh, take a break, or retrieve something from your hotel room at the host site rather than going cross-town to get it and bring it back. Ditto for taking a break, or getting together with other collectors in your hotel room at the Riv.