Though expected to be a popular addition to network television, the Once Upon A Time In Wonderland spinoff series failed to take off and wound up weakening the momentum of its original show, Once Upon A Time. The idea for the spinoff series came after its forerunning show became a sensation on small screens following the lives of classic fairytale characters like Snow White, Prince Charming, Captain Hook, and more. Once Upon A Time was an ABC hit that aired for seven seasons and had the endless potential to expand by introducing new fairytale favorites into the fold.

https://screenrant.com/once-upon-a-time-wonderland-failed-spinoff-explained/