Danny Rensch is an extremely busy member of staff that has a ton on his plate. He tries his hardest to do the show but sometimes unforseen occurances step in. Happens to all of us unfortunately.
Not all the shows are cancelled by the way. Just once in a while :-)
Every once in a while, chess.com puts on their chess.com/tv calander that there is gonna be a big show by some Raunch guy. Or whatever his last name is. Anyways, for some reason or another, it is always cancelled. Needless to say, this is terrible busisness practice. Telling people there's going to be a show and then flaking out at the last minute. Sure sounds like a real BIG disaster, not a big show, that's for sure.