How come these two weren't asked to do Dancing with the Stars?

Obviously, we don't expect model Victoria Silvstedt to have some sort of awesome career, but Shannen Doherty had more promise than hosting a reality break-up show titled "Breaking up with Shannen Doherty." To make matters worse, Shannen hung up on a Newsweek reporter for daring to bring up questions about her past relationships. Shannen's career is starting to look worse than Ian Ziering's.