* Privacy: The Kellers may have chosen to maintain their privacy and not participate in the spotlight that came with the show.
* Age and health: Jimmy and Mary Bobye were older, and they may not have been interested in the demanding schedule and travel required for filming.
* Focus on the Duggar family: The show was primarily about the Duggar family, and it's understandable that they chose to focus on their own story and the dynamics within their large family.
It's important to remember that we don't know the exact reasons why Michelle's parents weren't on the show. These are just some possible explanations.