The problem is that people dislike the `smooth' sensation of high-fps video in their films- is there really something magical about a multiple of 24 that would keep that jerky feel?
A multiple of 24 like, say, 120? I'd always thought that 120Hz TVs were being pushed because 120 is a multiple of both 24 and 30.
That was the original push, but lots of manufacturers botched the implementation. For example, some would apply 3:2 pulldown to 60hz and then double it instead of 5:5 pulldown. Nowadays 240hz are all the rage making movies look like a cheap karaoke video.