CogVideo was released only 4 months ago, you can see some samples on this page https://models.aminer.cn/cogvideo/. Statistical models can be used more efficiently (see KerasCV, https://news.ycombinator.com/item?id=33005585), and computing power can increase.

I don't think AI will be able to create a movie anytime soon, but I think it will become "good enough" to serve as inspiration for creatives, or to replace simple stock footage (Much like SD and DALLE-2 is now).