This is often exacerbated horribly by the fact that the 50 or 60 FPS output doesn't divide well by the 24 FPS source material. It was smoother in the cinema, when it was projected at 24 FPS...

Fair point, but I (and many others) see stutter in theatre as well.

Most of the reason you don’t is because filmmakers know very well what their “maximum pan speed” is and they stay as far away from it as possible.