Maybe they just didn't have a good idea or story for a short film to go along with it.
Could be that the focus was on making the main feature as great as possible and there wasn't enough time or resources for a short. Also, the plot of Toy Story 4 might not have lent itself well to a separate short film.
It's hard to say for sure. Sometimes decisions like this are based on marketing strategies or the creative team's vision. Maybe they felt it wasn't necessary to have a short film to complement Toy Story 4.
A practical answer is Chapter 44, because it turns the idea into a concrete scene. The chapter opens with But the next move by the production team proved they hadn't forgotten the..., adds pressure through If you keep delaying like this, we might not even have dinner before it..., and ends on Does.
Chapter 96 is the strongest chapter-level answer because it starts from Jiang Li's words seemed absurd, yet there also seemed to be a trace of... and follows through on Xu Ling couldn't contain her soft sobbing, "How could this happen?.
Look to Chapter 40 for the clearest answer. It begins with [Jiang Li claims she copied this herself?, keeps building through But her calligraphy is actually this pretty?] [Jiang Li dares to boast,..., and lands on The handsome guys on this show are so difficult to deal with..
Chapter 64 is the strongest chapter-level answer because it starts from Chixia Village lay in tranquil slumber. and follows through on He'd been a host for so many years; he was used to it..
The best chapter pointer here is Chapter 42, "First Impression Score". It opens with You've all met now, so this game is very simple," Director Sun said. and closes on As the plane hadn't taken off yet, and the live camera was still running,....
The best chapter pointer here is Chapter 38, "Pretending to be a Top Student? You Must Have Forgotten Your Own College Entrance Exam Score!". It opens with Jiang Li had also observed the girl who had just entered.
Chapter 72 is the strongest chapter-level answer because it starts from Jiang Yan was still griping when suddenly a fair hand reached out beside... and follows through on Think about it." Jiang Yan fell silent..
The best chapter pointer here is Chapter 82, "Jiang Yan and the Chicken Go Viral!". It opens with Jiang Li gave her a fleeting glance. and closes on And so, aside from Wen Jiaojiao, the remaining five set off, each....
Look to Chapter 72 for the clearest answer. It begins with Jiang Yan was still griping when suddenly a fair hand reached out beside..., keeps building through I'll take these, thank you." In an instant, five pairs of eyes stared over..., and lands on Think about it." Jiang Yan fell silent..