Here is a brief history on animation techniques. The history shows that animation has improved by doing various techniques.
From Shahr-e Sukhteh, a pot showing goats leaping which shows animation from the goat being in different position. To the many more techniques in animation like flip books, Zoetrope, drawn animation. The development from style has improved as well. From the silent era which was mainly black and white to more modern times with improvements with colours and the style of animation shows animation is improveing on the variority of animations style and techniques. The more common modern animation now a days, show there is more 3D than 2D animations as 2D animation is harder than 3D as 2D is mainly the best when doing draw frame by frame which takes a long time to do.