[Springtime]

Lottie[1], an Adobe After Effects plugin, fills a gap in vector animation authoring and is quite widely used (primarily in mobile applications but also works on the web, Discord for example supports them for stickers).

It's a pity SVG animation authoring tools never eventuated since it's an underutilized but useful native format. Though I know Blender allows for SMIL export via its Freestyle feature (the animation is effectively frame-by-frame only though, not leveraging SMIL's path interpolation/morph ability).

[1] (ignore the GIF-converted examples, the originals are lightweight and vector-based) https://airbnb.io/lottie/

[yreg]

We use tons of vector animations in the UIs, but I guess what the GP meant are animations in the form of short movies like Happy Tree Friends or Animator vs. Animation. That style is no longer popular and it used to be everywhere.

As for the cause, I think it's not only that Flash is dead, but also that there are now many other easy options to create content including professional looking video and much more refined animations. That wasn't an option 20 years ago for most.