Often, the right decisions are the hardest ones. Certainly applies in this case as television's Castle has not been renewed for Season Nine. It's a good thing as the chemistry between lead actors Nathan Fillion and Stana Katic made the show work.
Cast and crew of Castle.
That's not a jab to downplay the wonderful ensemble cast at all- but the ongoing Castle / Beckett romantic tension gave the series a spark that did not go out even once the two finally married.
Stana's goodbye note via Instagram.
ABC Television under the leadership of the Walt Disney Company could have done what they have done to other Disney divisions under the leadership of Robert Iger: Let the series continue without Stana so they could go on stuffing their pockets with more cash. (Just look at the state of the U.S. Disney parks in Florida.) However, for once, common sense and perhaps the respect of the art won out. Castle would not continue without Stana. Or perhaps Disney had no choice...
Can the suits make the same decision for The Twilight Zone Tower of Terror and not convert it into a Guardians of the Galaxy attraction? Probably not.