There are three types of animation: hand-drawn or 2D, CG, and stop-motion. Stop-motion is when an object is moved very slightly and then photographed. Several photos are done until each object moves believably.
Usually, stop-motion animation is done with puppets. Examples include those Christmas specials like “Rudolph the Red-nosed Reindeer” and “Santa Claus is Coming to Town”. Then there are more recent examples, like “Paranorman” and “Box-Trolls”. There is also another kind called Claymation, where the animators use clay models instead of puppets. A couple examples include “Wallace and Gromit” and “Early Man”.
While stop-motion films look fantastic, I notice there are not too many. Why is that, you may wonder? I think it’s because they are extremely time-consuming.
Before CGI was invented, most animated movies were 2D and drawn with pencil and paper. There were some stop-motion films, like “The Nightmare Before Christmas”. Then, after the turn of the century, when 2D animated films were dying out, and CG animation was booming, the number of stop-motion movies have pretty much remained the same.
Stop-motion animation may involve lots of skills, patience, and time, but I don’t know if they will increase the number of films, or decrease them.
Yes, there have been advancements, like the use of special effects in movies, like “Paranorman”. And I’m sure that involves more work, therefore, more time.