I think they are evolving differently. Some very old cgi holds up because they invested a lot of money to make it so. Then they tried to make it cheaper and people started complaining because the output was worse than all prior options.

Jurassic Park is a great example - they also had excellent compositing to hide any flaws (compositing never gets mentioned in casual CGI talk but is one of the most important steps)

The dinosaurs were also animated by oldschool stop motion animators who were very, very good at their jobs. Another very underrated part of the VFX pipeline.

Doesnt matter how nice your 3D modelling and texturing are if the above two are skimped on !