ABC president Channing Dungey didn’t even site the drop in ratings for the show’s cancellation, instead pointing to “behind-the-scenes churn” which led to the series seeing a number of showrunners come and go in a short time.
Unfortunately, Designated Survivor’s ratings fell pretty hard in Season 2.
And, while star Sutherland thought, in April 2018, that the show had a solid shot at getting renewed, Designated Survivor was cancelled about a month later.
This turnover led the network to feel less than sure about the creative direction, and this (probably combined with the decline in ratings) led to show’s demise.