2D animation has slowly died out, with it being replaced by dull, boring 3D animation. Most animated movies now are animated using computers, and I'm not a fan of this. I'm going to talk about the history of 3D animation and why I dislike it.
During the renaissance era of Disney (the 90's), instead of traditional hand drawn animation, computers were used to help scale certain scenes that would be impossible to animate using trad hand drawn animation techniques, an example of this is the ballroom scene in Beauty And The Beast.
Then in 1995, Pixar released Toy Story, the studio's movie debut and the first fully computer animated film made.
Then in the 2000's 3D animation became more and more popular with Pixar being a very well respected studio. In 2006 Disney bought Pixar.
In the 2010's Disney switched to 3D animation, around this time there was also more computer animated shows, with a lot of kid's TV being digitally animated.
Why I dislike 3D animation
Computer animated movies/shows look lifeless, dull. It has a cheap look, hand drawn animation takes ages, and you can see all the effort and emotion just flowing through every frame, but I could create a 3D model for a computer animated film on MS Paint 3D.
It also lacks expression and flexibility- this may seem odd, but think of the scene in Aladdin where Aladdin is running away from guards in the town. Think of all the exaggerated movements, how flexible the characters are. This scene would not work with 3D animation, because 3D models aren't as expressive, they're more dull.
3D animation also ages poorly. Look at Disney's first film Snow White, and see how the animation holds up, it still looks beautiful. Now see Pixar's first movie Toy Story, it doesn't look bad, but it doesn't look good as well. Computer animated movies/shows don't hold up well, in a few decades Encanto is going to look like crap.
Animation Flexing is a term I have created to describe something that happens a lot in digitally made movies. This occurrence happens when a computer animated film has hyper realistic backgrounds, but then has basic, cartoony humans/animals placed in this world. It's jarring to see these basic people placed in a photo realistic environment, it's like the animation studio is saying "Hey look at what we can do! Look at how realistic the backgrounds are, we're so talented!", they're flexing about what they can animate, hence the name Animation Flexing.
So that's why I dislike 3D animation, I think it's sad that hand drawn and 2D animation is a thing of the past, and it needs to come back.
NOTE: I'm talking about western animation, Japan has stuck to 2D animation, but I don't know how long that it will stay that way, because Studio Ghibli recently made a 3D animated movie, and with the video game industry (which is dominated by Japan) taking influences from Hollywood with remaking/making sequels to old properties it probably won't last.