John Stamos is partly to blame for the Olsen Twins Fuller House absence, due to Mary-Kate and Ashley Olsen’s decision to pass on the reunion project in 2016. Netflix released the spin-off sequel to the beloved ’80s/’90s family sitcom, Full House, with the main cast all returning except the Olsen twins in their shared role as Michelle. The youngest Tanner sister was nowhere to be found after Fuller House failed to convince the Olsen twins to join the show. Instead, Kimmy the Tanners’ long-time neighbor became a lead character in the sequel, effectively taking over Michelle’s would-be spot.
https://screenrant.com/fuller-house-john-stamos-mary-kate-ashely-missing-fault/